Arandom sample of 20 houses selected from a city showed that the mean size of these houses is 1880 square feet with a standard deviation of 320 square feet. assume that the sizes of all houses in this city have an approximate normal distribution. the upper bound the 90% confidence interval for the mean size of all houses in this city is: a. 2110 b. 1941 c. 1974 d. 1968 e. 1894

Option C

Step-by-step explanation:

Given that for a  random sample of 20 houses selected from a city showed that the mean size of these houses is 1880 square feet with a standard deviation of 320 square feet.

X, the sizes of houses is Normal

Hence sample mean will be normal with

Mean = 1880

and std dev =

For 90% confidence interval critical value for t with degree of freedom 19 is

1.328

Confidence interval upper bound

= mean + margin of error

=

Option C is right

she was supposed to add the hours(38.5) and multiply the amount of money she earned(7.50) resulting in $288.75 .

correct me if i'm wrong and if it is i'm truly sorry.

step-by-step explanation: