Question

A random sample of 145 students is chosen from a population of 4,250 students. The mean IQ in the sample is 130, with a standard deviation of 7. Using a margin of error of 0.95%, what is the 90% confidence interval for the students' mean IQ score?

Answer 1

Answer:

Approximately, the 90% confidence interval for the students' mean IQ score is between 129.045 - 130.956

Step-by-step explanation:

The formula to use to solve this question is called the Confidence Interval formula.

Confidence interval =

x ± z × ( σ/ (√n) )

Where:

x = the sample mean = 130

z = the z-value for 90% confidence = 1.645

σ = standard deviation = 7

n = sample size = 145

130 ± 1.645 × (7/√145)

130 ± 0.9562687005

130 - 0.9562687005 = 129.0437313

130 + 0.9562687005 = 130.9562687005

Therefore, approximately, the 90% confidence interval for the students' mean IQ score is between 129.045 - 130.956