Question

In the population, the average IQ is 100. A team of scientists wants to test a new medication to see if it has either a positive or negative effect on intelligence or no effect at all.

A sample of 30 participants who have taken the medication has a mean of 140 with a standard deviation of 20. Did the medication affect intelligence?

without handwriting, please.

Answer 1

H0: $\mu$ = 100

Ha: $\mu$ $\neq$ 100

Test statistics

t = ($\bar{x}$ - $\mu$ ) / (S / sqrt(n) )

= P(Z < (140 - 100) / (20 / sqrt(30) )

= 10.95

Critical values at 0.05 level with 29 df = -2.045 , 2.045

Since test statistics falls in rejection region , Reject H0.

We conclude at 0.05 level that we have sufficient evidence to support the claim that the medication

affect intelligence.