Question

x	7	10	8	4	3
y	8	11	9	5	4

a.	Calculate the covariance between the variables. (Negative value should be indicated by a minus sign. Round your intermediate calculations to 4 decimal places and final answer to 2 decimal places.)

b-1.	Calculate the correlation coefficient. (Round your intermediate calculations to 4 decimal places and final answer to 2 decimal places.)

b-2.	Interpret the correlation coefficient.

There is _____ no, a weak negative, a weak positive, a strong negative, a perfect positive, a strong positive relationship between x and y.

_______________________________________________________________________________________

The National Sporting Goods Association (NSGA) conducted a survey of the ages of individuals that purchased skateboarding footwear. The ages of this survey are summarized in the following relative frequency distribution. Assume the survey was based on a sample of 200 individuals.

Age of User	Percent
Under 14 years old	23
14 to 17 years old	40
18 to 24 years old	18
25 to 34 years old	7
35 to 44 years old	7
45 to 64 years old	5

Calculate the mean and the standard deviation of the age of individuals that purchased skateboarding shoes. Use 10 as the midpoint of the first class. (Do not round intermediate calculations. Round your answers to 2 decimal places.)

Mean
Variance
Standard deviation

_______________________________________________________________________________________

A manager of a local retail store analyzes the relationship between advertising and sales by reviewing the store’s data for the previous six months.

Advertising (in $100s)	Sales (in $1,000s)
205	129
56	44
55	43
54	42
169	139
203	127

a.	Calculate the mean of advertising and the mean of sales. (Round your answers to 2 decimal places.)

	Mean
Advertising
Sales

b.	Calculate the standard deviation of advertising and the standard deviation of sales. (Round your answers to 2 decimal places.)

	Standard Deviation
Advertising
Sales

c-1.	Calculate the covariance between advertising and sales. (Round your answer to 2 decimal places.)

c-2.	Interpret the covariance between advertising and sales.
	Positive correlation No correlation Negative correlation

d-1.	Calculate the correlation coefficient between advertising and sales. (Round your answer to 2 decimal places.)

d-2.	Interpret the correlation coefficient between advertising and sales.
	Weak positive correlation No correlation Strong negative correlation Weak negative correlation Strong positive correlation

Answer 1

3002 tro ng ose atoo