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

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)