# Statistics Essay

CH1

In an observational study, researchers simply observe characteristics and take measurements, as in a sample survey.

In a designed experiment, researchers impose treatments and controls and then observe characteristics and take measurements.

Data from a sample of citizens of a certain country yielded the following estimates of average TV viewing time per month for all the citizens.

Answer: Inferential, because the statistics are used to make inference about the population.

* 50 kids are divided into 2 groups. One is exposed to a vid on bullying. The other isn’t. After one week, both groups are questioned about their attitudes about violence. This is a designed experiment

5 state officials:

*…show more content…*

b) identify pie chart ( has same percentages as relative freq) c) bar chart ( not connected height matched relative freq.)

4. Questionaire with score results: 37 | 15 | 44 | 24 | 16 | 22 | 46 | 53 | 12 | 52 | 31 | 35 | 43 | 18 | 53 | 38 | 30 | 44 | 45 | 46 | 21 | 17 | 44 | 37 | 35 |

a) determine frequency distribution: Anxiety | Frequency | 12-18 | 5 | 19-25 | 3 | 26-32 | 2 | 33-39 | 5 | 40-46 | 7 | 47-53 | 3 |

Grouping is given by one, group the others like above. Then CAREFULLY tally them for the right column

b) obtain relative frequency: Anxiety | Relative Frequency | 12-18 | .2 | 19-25 | .12 | 26-32 | .08 | 33-39 | .2 | 40-46 | .28 | 47-53 | .12 |

RF = FN / (F1+ F2 +F3…)

c) frequency histogram (connected, highest point number for frequency)

d) rel freq. histogram (connected, highest point number for rel. frequency)

5. average height:

29.5 28.4 29.1 27.2 a) stem + leaf 27 2

30.1 30.1 29.4 28.4 28 3 4 29 1 2 5 30 1 1

B) stem + leaf (two lines per stem)

27 2

28 3 4

29 1 2

29 5

30 1 1

(all numbers 0-4 on