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61 Cards in this Set
- Front
- Back
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What are the "Rounding Rules" in Statistics?
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1) Start Calculating your answer from four decimal places, but your final answer must end in THREE
(Excluding which method of calculation?) 2) If the fourth digit is less than 5, report the first three digits WITHOUT change. 3) If the digit is 5 or greater, increase the third digit by 1. * 1/7= 0.142857143 rounded to the thousandths place is 0.143 * |
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A Hypothesis
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A possible explanation for the behavior being studied that is based on previously gathered facts and theories.
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What is Statistics?
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A special brand of Applied Mathematics
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A Research Hypothesis is...
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Is a statement that a researcher wish to support. A positive statement which is derived from the research question.
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A Null Hypothesis is...
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Is a statement that a researcher wants to reject because it proposes that there will be no change in behavior, no difference between the groups being measured.A negative twist on the research hypothesis.
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Research Question
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A question derived from the hypothesis.
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What are Variables?
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Are events of qualities that can vary- they can assume more than one value. They include factors as reaction time, number of participants in a group, number of aggressive acts, etc.
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Independent Variable (IV)
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Is selected and manipulated/controlled by the researcher. It is independent of anything the participant does.
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Dependent Variable (DV)
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Is a measure of behavior exhibited by the participant. It is dependent of the independent variable. They are the scores and outcomes from your data.
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What is a good way to determine which variable is IV or DV?
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Reword the research question:
What is the effect of (IV) on (DV)? What is the effect of THE TYPE OF FILM VIEWED BY THE CHILD (IV) on THE NUMBER OF AGGRESSIVE ACTS PERFORMED BY EACH CHILD? (DV) |
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What are Extraneous Variables and how do they effect an experiment?
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Something that is extra which could mess up a study such as noise, hunger, time of day, temperature. It may affect the outcome of the experiment but is not directly related to the study.
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Nominal Scale
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The word NOMINAL means "name". It is the simplest form of measurement and is used when the variable being measured (DV) is qualitative as opposed to quantitative.
Ex: It is QUALITATIVE. Gender, Age, Height, Weight, Socioeconomic Level, etc. |
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What are the problem with a Nominal Scale of Measurement?
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It cannot be used for anything else but QUALITATIVE comparisons.
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What is an Ordinal Scale?
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It requires that you order, or rank, the data from highest to lowest.
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What is the problem(s) with using an Ordinal Scale of Measurement?
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They show relative rankings BUT reveal nothing about the extent of the differences between the rankings. Equal distances do not necessarily represent equal differences between the participant's qualities.
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What is an Interval Scale?
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It's a scale of measurement that indicates not only relative ranks of scores but also EQUAL DISTANCES or degrees of difference between the scores. Thus, the scores of 1 and 2 are the same as 3 and 4.
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What is a major disadvantage of using the Interval Scale?
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It does not allow you to make ratio types of comparisons.
NOTE: Without a meaningful zero-point, ratio comparisons cannot be made. So a person with an IQ of 120 is not TWICE as smart than a person with an IQ of 60. |
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A Ratio Scale
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It contains a meaningful zero-point which makes ratio comparisons possible. The AMOUNT or the NUMBER OF.
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Qualitative Studies vs Quantitative Studies
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Qualitative= A study of a person's QUALITY.
EX: Height, Weight, Gender, GPA, Car they Drive, Opinions and Attitudes etc. Quantitative= A score, QUANTITIES Ex: The Dean of SWC would like to know the SCORES of every single student on their math test. |
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What is a Frequency Distribution?
(Chapter 2) |
A type of Statistic with lots of data and requires organization.
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List the kinds of Frequency Distributions there are and what they acquire (Ch. 2)-
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Simple Frequency Distribution
Group Frequency Distrubition Ranked Distribution Simple= It has less than or equal to 20 subjects in the study. Grouped= It has greater than 20 subjects. Ranked= 6 basic steps, created by ordering the scores together provided by the raw data (unorganized scores). |
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How is a Ranked Distribution organized? (Ch. 2)
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6-steps
A) Put scores in descending order (highest number at the top, lowest at the bottom) B) Compute the range C) Determine number of Intervals D) Determine Interval Size (i=range/x) E) If it's a grouped distrib. put data into CLASS INTERVALS and compute other data. |
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Simple Frequency
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Contains Scores and Frequency only.
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What is a Sample Study and how is it written?
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It is a relatively small representative group selected from a population
Statistical notation- lowercase"n" EX: If you take an entire classroom and only interview every five students, that is a sample study. A POPULATION study takes the ENTIRE student class for the experiment. |
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Population Study
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Includes ALL of the members of a certain group. It may be large or small but it includes everybody.
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Aside from IV and DV, what is another variable that is involved that is considered Qualitative?-
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A Subject Variable
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In a Group Frequency, what is included in the study? (In ORDER!)
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R-A-f-Cf-rf-Crf-CP-M
Real Limits, Applied Limits, f (frequency), Cf (Cumulative frequency), rf (Relative frequency), Crf (Cumulative Rel. Freq.), C% (Cumulative %), and Midpoint. |
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What is the order of the Basic Flowchart?
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1a) Generate Research Question
1b) Develop Ideas as a possible answer (research hypothesis) 2) Find a Literature Review 3) Choose a Method to test your hypothesis- Natural Observation, Case Study, Survey/Questionnaire, Correlation Study of 2 variables, Formal Lab Experiment. 4) Results (site important data findings) 5) Discussion (what was learned) 6) Cite References. |
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Statistics that describe population values such as the mean (average) are called...
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Parameters
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Round these numbers to 3 decimal places-
a) 13.234473 b) 15.77377 c) 24.999999 |
a) 13.234
b) 15.774 c) 25.000 |
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No matter what kind of data you collect, they will be recorded on one of four measurement scales which are:
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Nominal, Ordinal, Interval, and Ratio scales.
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Find the DV and IV:
A researcher has two groups of identical nerve cells living in separate dishes. He proposes to apply different concentrations of a nerve-blocking agent to the groups of nerve cells and to measure any change in the number of impulses generated by the nerve cells. |
IV- To apply different concentrations of a nerve blocking agent to nerve cell groups.
DV- To measure change in the number of nerve cells generated by the nerve cells. |
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Create a Research and Null hypothesis with this statement:
Is there a difference between the number of personality traits exhibited by 3-year olds as compared to adults? |
a) There will be a difference in personality traits between 3-year old children and adults
b) There will be no differences in personality traits between 3-year old children and adults. |
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23) The number of errors made on a color vision test?
19) Class rank? 25) The number of stressful events that you've experienced in the last 6 months? * The time it takes to solve a puzzle? |
23) Ratio Scale
19) Ordinal Scale 25) Ratio Scale * Interval Scale |
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Class Intervals are..
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Raw Data combined into equal-sized groups for group frequency distributions.
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Putting a group of scores into a Ranked Distribution means to...
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Simply put the scores in descending order.
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To find the range, what is the formula?
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Range = Highest Score- Lowest Score
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To find the approximate interval size in a grouped frequency distribution, which formula do you use?
a) z = X-X / S b) i = Range/# of intervals c) # of intervals = Range / i d) Both B & C |
Both B & C are formulas used to find the number of intervals.
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To find the midpoint in a Grouped Frequency Distribution, what formula do you use?
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Midpoint= Lower limit + Upper Limit / 2
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How do create a Grouped Frequency Distribution? (IN ORDER!)
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1) Compute the range
2) Choose your interval size (which must be between 10-20 class intervals! i= range / i 3)Create Class Intervals a) All lower app. limits must be a multiple of i. b) MUST be the same size c)Highest class interval must contain the highest score. d) Lowest interval must have lowest score. 3) Compute Real Limits 4) Tally Frequencies 5) Find the Midpoint * lower limit+ upper limit / 2 |
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The first step in summarizing data is to rearrange the data in order from highest to lowest scores, which is called a ________ _________.
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Ranked Distribution
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How is Relative Frequency calculated?
How about Cumulative Relative Frequency? |
RF = Frequency / n
CrF = Cumulative Frequency / n |
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Cumulative percent if found using what formula?
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Cumulative Relative Frequency x 100
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Create a ranked distribution for the following numbers of third-born children who graduated from 25 high schools in Escuela Nueva County last year:
67 54 39 77 54 46 54 59 86 34 55 61 49 43 71 56 63 77 70 52 50 46 33 41 55 |
8- 86
7- 70, 71, 77, 77, 6- 61, 63, 67 5- 50, 52, 54, 54, 54, 55, 55, 56, 59 4- 41, 43, 46, 46, 49 3- 33, 34, 39 86, 77, 77, 71, 70, 67, 63, 61, 59, 56, 55, 55, 54, 54, 54, 52, 50, 49, 46, 46, 43, 41, 39, 34, 33 |
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The price of new automobiles at a local dealer varies from a low of $10,023 to a high of $52,298. Compute the Range.
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Range = Highest Score- Lowest =
$52,298 - $10,023= $42,275.00 |
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A Frequency Histrogram is...
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Is a graph that consists of a number of bars placed side by side.
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A Frequency Polygon is...
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Is a type of graph that uses a single point rather than a bar to represent a class interval on a graph.
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Relative Frequency Polygons
(Ch. 3) |
To compare two graphs in one.
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While graphing, which axis goes on the bottom and which axis goes on the side?
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X- axis is always placed on the bottom
Y-axis is located on the frequency side, which is on the sides. |
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While creating a Grouped Frequency Chart, your n= ?
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(lowercase) n = frequency
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Cumulative Frequency Polygon is...
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The upper real limit is the most representative place to plot each point.
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Any set of raw scores is the sum of all the scores divided by the total number is scores is computing the ____.
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Mean
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Computing the Mean from Raw Scores. If you have a POPULATION Study...
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1) Find the Total number of scores = N (Upper Case!)
2) Sum of the scores (sigma)X 3) Compute the mean of the population = Mean= (sigma)X / N |
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Computing the mean for a SAMPLE Study
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1) Total number of scores = n (lower case!)
2) Sum of the scores (sigma)X 3) Compute the mean of the Sample= MeanX = (sigma)X / n |
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To find the median, there are 2 ways to compute it. What are they?
(Pg. 100 will help) |
1) Formula = 2 middle scores =
76+74 / 2= 75 2) L+[(n/2) - CFb / Fi ] x i * L = The lower real limit * n = The # of scores in the entire distribution. * CFb = Cum Freq. in the class interval BELOW the class interval that contains the median. * Fi = The Freq. in the class interval that contains the median. * i = The class interval size. |
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Find the mean, median and mode of the following welding aptitude test scores.
23 25 27 22 35 45 29 26 33 34 25 27 25 29 33 |
Ranked Distribution:
22 23 25 25 25 26 27 27 29 29 33 33 34 35 45 * Mean: 438/15= 29.20 (added all of the scores divide by number of scores) * Median: 27+29/2= 28 * Mode: 25 (the # most repeated) |
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Measures of Variability
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It gives an idea of how much scores in the distribution vary from that one average score. (pg 112)
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Variance of Population Formula
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Variance of a population =
(lowercase Greek letter sigma squared)= (sigma)(X-mean)2 / N = (sigma) x (squared) / N |
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Variance of a Sample Formula
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S(squared)= (sigma)(X-Mean)(squared) / n-1 = (sigma)X (squared)/ n-1
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n = _________
N = _________ |
n= Sample Study
N= Population Study |
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Memorize pg 121 formulas for Variance and Standard Deviation.
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please ;)
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