1. Math
  2. Statistics And Probability
  3. x 7 10 8 4 3 y 8 11 9...

Question: x 7 10 8 4 3 y 8 11 9...

Question details
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
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