Arandom sample of 150 students has a grade point average with a
mean of 2.86. assume the population standard deviation is 0.78.
construct the confidence interval for the population mean, u, if
c = 0.98.

2.7065 to 3.0135

Step-by-step explanation:

1. find the z-score

zscore=(value {or c in this case} - mean) / standard deviation

= (.98 - 2.86) / .78

= - 2.4102

2. find the confidence interval

confidence int= mean (+ or -) zscore x (standard diviaion) / the square root of n

=2.86+\- -2.4102 (0.78) / square root of 150

=2.86 +\- -0.1535

It's proportional. Hope this helps. . .