Answer: 0.6827
Step-by-step explanation:
Given : Mean IQ score :
Standard deviation :
We assume that adults have IQ scores that are normally distributed .
Let x be the random variable that represents the IQ score of adults .
z-score :
For x= 90
For x= 120
By using the standard normal distribution table , we have
The p-value :
Hence, the probability that a randomly selected adult has an IQ between 90 and 120 =0.6827
Answer:
Step-by-step explanation:
Given that :
the null and the alternative hypothesis are computed as :
This is a two tailed test
This is because of the ≠ sign in the alternative hypothesis which signifies that the rejection region in the alternative hypothesis are at the both sides of the hypothesized mean difference .
Decision Rule: at the level of significance ∝ = 0 . 10
The decision rule is to reject the null hypothesis if z < - 1 . 64 and z > 1 . 64
NOTE: DURING THE MOMENT OF TYPING THIS ANSWER THERE IS A TECHNICAL ISSUE WHICH MAKES ME TO BE UNABLE TO SUBMIT THE FULL ANSWER BUT I'VE MADE SCREENSHOTS OF THEM AND THEY CAN BE FOUND IN THE ATTACHED FILE BELOW
