Question

Question #2af0c

Answer 1

`CI_(95%)" "(134.88,155.12)`

Explanation:

for a confidence interval we calculate

`barx+-zsigma/sqrtn`

we are not told the distribution but since`" "n>30` we can use the Central Limit theorem which states that the distribution of the sample means will be approximately Normal

for a `95% CI`

`z=1.96`

we have

`145+-1.96xx40/sqrt60`

`=145+-10.12(2dp)`

`CI_(95%)" "(134.88,155.12)`