exam 2 diamond

Question 1

experimental unit

Answer 1

a diamond

Question 2

dependent

Answer 2

price (in dollars $)

Question 3

independent

Answer 3

size of the diamond (carats)

Question 4

The line shown on the scatterplot…

Answer 4

does not represent the true line of means of population mean or dependent variable y.

Question 5

95% confidence interval for true slope

Answer 5

plug in carat (carat = B1)
SE = standard error
plus and minus then you have your two numbers.

We are 95%confident that for every 1 carat increase in size (carat), price increases between 11,138.7 and 12,059.1

Question 6

if no practical interpretation is possible, explain why

Answer 6

no practical interpretation, since price being equal to zero is nonsensical. Also, a diamond of 0 carats is nonsensical.

where the global # is at. you cannot have a negative carat or a negative age. no practical interpretation. Nonsensical.

Question 7

correlation coefficient means that there is evidence of a

Answer 7

strong, positive, linear relation btw size (carats) and price (dollars)

Question 8

determine whether y is linearly related to x in simple linear regression model

Answer 8

Ho: B1 = 0 Ha: B1 not equal to 0
alpha = .05 p= o.oooo
reject Ho

sufficient evidence of a linear relationship between price (in dollars) and size of a diamond (in carats)

Question 9

x you selected for your 95% prediction interval for y

Answer 9

since the value of x is within the range of the sample, the interval is valid