Question

Determine the (intended) population and sample for each of the following:

a. DeWayne wants to know how students at the University of Hawaii feel about country music. He asks 70 people in his introductory psychology class to fill out a survey about country music.

b. Terry wants to sell her new product to people in Oklahoma. She calls 200 people from the Oklahoma City phone book and asks them what sorts of characteristics they would like in a product like hers.

2. The following data is taken from an undergraduate class and represents the number of hours that they reported studying in one week:

Number of Hours Study Per Week

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

4 4 4 4 4 4 4 4 4 4 4

5 5 5 5 5 5 5 5 6 6 6 6 6 6 6

7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7

8 8 8 8 8 8

9

10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10

12 12

13

14 14 14

15 15 15 15 15 15 15 15

16 16

20 20 20

24

25 25 25 25 25 25 25

26

30

a. (6 points) Form a frequency, relative frequency, cumulative frequency, and cumulative relative frequency distribution. Use an interval of 3 (e.g., 3-5, 6-8, etc). See p. 33.
b. (6 points) Based on the above, form a histogram and a frequency polygon. Use the interval midpoints for graphing on the x-axis (e.g., 4, 7, etc.). See pp. 36-37. Why do we use a histogram instead of a bar graph?

3. Ten college students watch 3 half-hour news programs. Then, they are asked to recall as many of the news items as they can remember. Listed is the number of items they recalled.
1 7 4 3 4 4 3 8 5 2
a. (6 points) What is the mean? The median? The mode?
d. (8 points) The range? The variance? The standard deviation?

Answer 1

#1)

a) population : all students at the University of Hawaii

sample : 70 surveyed people in his introductory psychology class.

b) population : all people in Oklahoma city.

sample : 200 called people from the Oklahoma City.

#2)

Frequency : it is count of numbers in data set belonging to the corresponding interval.

Midpoints : ( lower limit + upper limit ) /2

Cumulative frequency : it is the running total of the frequencies.

For first interval the cumulative frequency would be the frequency of 1st interval, then to find cumulative frequency of 2nd interval we add the frequency of 2nd interval to the cumulative frequency of previous interval (1st interval ), so to find next cumulative frequencies  we goes on adding the frequency of corresponding class interval to cumulative frequency of previous class interval.

Relative frequency : $\frac{Frequency }{Total. frequency }$

For example : Frequency =

a) So for the given data set we will get the frequency, relative frequency, cumulative frequency, and cumulative relative frequency distribution as shown in the following table :

b) We can draw the histogram and frequency polygon using excel.

Just select the all frequencies and go to Insert menu ---> Charts ---> For histogram select Clustered column chart and for frequency polygon select Line chart .

To get the midpoints on x axis , click on the histogram , then right click ---> "Select data" option ---> click on edit tab under horizontal axis labels , then in axis label range : select the all midpoints.

Bar chart is used for representation of qualitative or categorical data set and histogram is used for representation of quantitative or numeric data.

The given data set is quantitative , therefore we used histogram.