Arandom sample of 49 text books purchased at a local bookstore showed an average price of $122 with a population standard deviation of $15. let u (new) be the true mean cost of a text book sold by this store. construct a confidence interval with a 90% degree of confidence. clearly label the following:
a. point estimate
b. critical value,
c. margin of error
d. confidence interval
e. interpretation (confidence statement).

Step-by-step explanation:

Confidence Interval can be calculated using P±ME where

And margin of error (ME) can be calculated using the formula

ME= where

Margin of error, ME= = 3.525

Then 90% confidence interval is $122±3.525

To interpret this, there is 90% probability that true population average price of text books is in the range $122±$3.525

2.

according to newton’s cannonball model, what happens if the cannonball's velocity is enough to overpower the pull of earth’s gravitystep-by-step explanation:

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40