Question

Which of the following is not a characteristic of the chi-square distribution? Select all correct answers.

Select all that apply:

• The chi-square curve is symmetrical.

• The chi-square curve is skewed to the left.

• The total area under the χ2-curve is equal to the degrees of freedom, df.

• The total area under the χ2-curve is equal to 1.

Does buying CDs depend on whether you own a smartphone or not? A survey asks a group of students if they buy CDs or not. It also asks if the students own a smartphone or not. The data are recorded in the contingency table below, and a chi-square Test of Independence at the 5% significance level is performed.

	CDs	No CDs	Row Total
Smartphone	6	24	30
No Smartphone	16	8	24
Column Total	22	32	54

(a) The null and alternative hypotheses are:

• H0: The two variables are independent, so owning a smartphone does not affect buying CDs.
• Ha: The two variables are dependent, so owning a smartphone does affect buying CDs.

(b)  Compute the test statistic, rounded to one decimal place. (Use expected frequencies that are also rounded to one decimal place.)

Provide your answer below: test statistics =  

Horace keeps track of the amount of time he studies and the score he gets on his quiz. The data are shown in the table below. Which of the scatter plots below accurately records the data?

Hours studying	Quiz score
1	4
2	6
3	7
4	8
5	9

Select the correct answer below:

A scatterplot has a horizontal axis labeled Hours studying from 0 to 10 in increments of 2 and a vertical axis labeled Quiz score from 0 to 6 in increments of 1. Five plotted points strictly follow the pattern of a line that rises from left to right and has the following coordinates: left-parenthesis 4 comma 1 right-parentheses; left-parenthesis 6 comma 2 right-parentheses; left-parenthesis 7 comma 3 right-parentheses; left-parenthesis 8 comma 4 right-parentheses; left-parenthesis 9 comma 5 right-parentheses. Each point is labeled with its vertical coordinate.

A scatterplot has a horizontal axis labeled from 0 to 6 in increments of 1 titled Hours studying and a vertical axis labeled from 0 to 10 in increments of 2 titled Quiz score. The following points are plotted: left-parenthesis 1 comma 4 right-parenthesis; left-parenthesis 2 comma 6 right-parenthesis; left-parenthesis 3 comma 7 right-parenthesis; left-parenthesis 4 comma 9 right-parenthesis; left-parenthesis 5 comma 8 right-parenthesis.

A scatterplot has a horizontal axis labeled from 0 to 6 in increments of 1 titled Hours studying and a vertical axis labeled from 0 to 10 in increments of 2 titled Quiz score. The following points are plotted: left-parenthesis 1 comma 4 right-parenthesis; left-parenthesis 2 comma 6 right-parenthesis; left-parenthesis 3 comma 7 right-parenthesis; left-parenthesis 4 comma 8 right-parenthesis; left-parenthesis 5 comma 9 right-parenthesis.

Answer 1