Statistics Quiz 1

Front 1

look at figure #1:

the percentage of students with more than $20.00 but less than $40.00 is closest to:

(a) 15 %
(b) 19%
(c) 26%
(d) 31%

Back 1

b 15%

Front 2

look at figure #1:
The third quartile for this distribution occurs in whihc class interval?

(a) 10-20
(b) 20-30
(c) 30-40
(d) 40-50

Back 2

(a) 10-20

Front 3

look at figure #1:
The median for this distrbution would be

(a) to the right of the mean
(b) to the left of the mean
(c) the same as the mean
(d) greater than 100.00

Back 3

(b) to the left of the mean

Front 4

Three randomly selected winter days had miniumum temperature of -4, 5, and 11 degrees F. The numerical value of the standard deviation for this sample is:

(a) 0
(b) 7.55
(C) 16.667
(d) 57.00

Back 4

(b) 7.55

Front 5

The aspect of a variable that describes what values the variable takes on and how often it takes on these is the:

(a) variance
(b) z-score
(c) median
(D) distribtion

Back 5

(d) distribution

Front 6

Look at Figure #2:

Approximately what percent of the students in group 1 had a pulse rate above the median pulse rate of the students in group #2:

(a) less than 25%
(b) more than 50%
(c) more than 75%
(d) 100%

Back 6

(c) more than 75%

Front 7

Look at Figure #2:
Which of the following statements is true:

(a) the mean of a sample is always greated than the std. dev. of the sample.
(b) the std. dev. for a data set with 3 observations must always be positive
(c) the 3Q of a data set must always be greater than the 10 of the data set
(d) the mean of a data set can be negative but the std. dev of a data set can never be negative.

Back 7

(d)

Front 8

You have the weights in grams of 17 adult fleas. Yoiu find the standard deviation of the weights to be .01745. The correct unit for the standard deviation in this problem is:

(a) no units--the standard deviation is just a number
(b) grams
(c) grams squared
(d) milligrams squared

Back 8

(b) grams

Front 9

Look at Figure #3:
The third quartile of the length of time worked for these 20 employees is:

(a) 5.5 months
(b) 59.5 months
(c) 75.5 months
(d) 67 months

Back 9

(c) 75.5 months

Front 10

There are threee children in a room, ages 8, 9, and 10. If another nine-year-old enters the room, the

(a) mean age will stay sam, but the SD will increase
(b) mean age will stay same, but SD will decrease
(c) mean age and SD will stay same
(d) mean age and std dev will increase

Back 10

(b) mean age will stay same, but SD will decrease

Front 11

Look at Figure #4:

Based on this pie chart, we may conclude that

(a) Jpanese cars get signifigantly lower gas mileage than cars of other countries. This is because their slice of the pie is at the bottom of the chart.
(b) more than half of the cars in the study were from the US
(C) Swedish cars get more gas milegages that are between those of Japs and US

Back 11

b

Front 12

The five number summary of set of data:

(a) is the mean, standard deviation, first quartile, and third quartile
(b) is the mean, median, mode, variance, and standard devation
(c) can be computed from the information in a stemplot
(D) is the minimum, the interquartile range, the mean, the median and the maximum

Back 12

c can be computed from the information in a stemplot

Front 13

The average salary of all female workers at a large plant is $35,000. The average salary of all male workers at the plant is 41000. If there are more females wokers than male workers at the oplant, then the average salary at the plant must be:

(a) exactly 38000
(b) larger than 38000
(c) smaller than 38000
(d) above 41000

Back 13

c smaller than 38000

Front 14

Look at Figure #5:

For this density curve, what percentage of the observations lie between 0.35 and 0.50?

(a) 0.075
(b) 7.5
(c) 15
(d) 75

Back 14

(b) 7.5 %

Front 15

Scores on a school exam are normally distributed with a mean of 68 and a standard deviation of 4.5. Using the 68-95-99.7 rule, what percentage of students score above 77?

(a) 2.5 %
(b) 5%
(c) 16%
(d) 32%

Back 15

(a) 5%

Front 16

The time to complete a standardized exam is appx. normal with a mean of 70 minutes and a standard devation of 10 minutes. Using the 68-95-99.7 rule, if studetns are given 100 minutes to complete the exam, what percentage of students will not finish?

(a) 5 %
(b) 1.5 %
(c) 1%
(d) 0.15%

Back 16

(d) 0.15 %

Front 17

Using the standard normal distribution tables, what is the area under the standard normal curve corresponding to Z < 1.15?

a) 0.1357
b) 0.8643
c) 0.8749
d) 0.9332

Back 17

(c) 0.8749

Front 18

The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 5% of the students fail the course, what is the lowest mark that a student can have and still be awarded a passing grade?

a) 57
b) 51
c) 44
d) 40

Back 18

(c) 44

Front 19

A stemplot of a set of data is roughly symmetic, but the data do no even approximately the 68-95-99.7 rule. We conclude that the data is:

(A) normal, but they are not standard normal
(B) standard normal
(c) not normal
(d) normal

Back 19

(c) not normal

Front 20

Assume the distribution of ACT scores is normal with mean = 20.9 and standard deviation=4.8. Assume the distriubtion of SAT scores is normal with mean=1026 and standard deviation = 209.

Jacob takes the ACT and scores a 29. Emily takes the SAT and achieves teh same z-score that Jacob scored on the ACT. Which number is closer to Emily's score on teh SAT?

(a) 1279
(b) 1219
(c) 1349
(d) 1379

Back 20

(d) 1379