Answer:
Step-by-step explanation:
Kevin would need at least a 96 to raise his mean test score to 90. Hope it helps :)
Answer:
(351.04, 368.96)
Step-by-step explanation:
Given that population mean= 360
Std devitaion = 4
margin of error = 2.5%= 0.025
Since population std deviation is known we can use Z critical value
For two tailed critical value for 2.5% would be
2.24
Margin of error = ±Critical value*std deviation
= ±2.24(4)
= ±8.96
Confidence interval =(Mean - margin of error, mean + margin of error)
=
53.2
40%=.4
.4 times 38 = 15.2
15.2+38=53.2
Thank me later