Answer:
The correct option is B.
Step-by-step explanation:
It is given that there is a strong, negative, linear relationship between x and y. where, x is the number of consecutive hours a worker has been assembling chainsaws and y is the number of chainsaws he can produce in an hour.
He finds that 70%of the variation in chainsaws produced per hour can be explained by the regression of y on x.


The slope is -0.7, therefore option B is correct.
M² is equivalent to the expression M x M .
Answer:
2 proportions z test
The two populations are named as residents from the first county and residents from the second county.
Step-by-step explanation:
This is testing hypothesis about the difference between two proportions.
When the proportions are tested if they are the test statistic
z= ( p^1-p^2)- (p1-p2) / √p₁q₁/n₁ + p₂q₂/ n₂
where p^1 is the proportion of success in the first sample and p^2 of size n₁ is the proportion of success in the second sample of size n₂ with unknown proportions of successes p1 and p2 respectively.
When the sample sizes are sufficiently large
z= ( p^1-p^2)- (p1-p2) / √p₁q₁/n₁ + p₂q₂/ n₂ is approximately standard normal.
The two populations are named as residents from the first county and residents from the second county.