Question

Question 12 (1 point) Suppose that IQs of adult Canadians follow a normal distribution with standard deviation 15. A random sample of 50 adult Canadians has a mean IQ of 115. We would like to construct a 94% confidence interval for the true mean IQ of all adult Canadians. What is the critical value z* to be used in the interval? (You do not need to calculate the confidence interval. Simply find z*. Input a positive number since we always use the positive z* value when calculating confidence intervals.) Report your answer to 2 decimal places. Your Answer: Answer

Answer 1

Solution :

The critical value Z* used to construct a 94% confidence interval is given as follows :

$\large Z^{*} = Z_{\frac{0.06}{2}}$

Using Z-table we get, Z_(0.06/2) = 1.88

$\large \therefore \mathbf{Z^{*} = 1.88}$

The required critical value is Z* = 1.88.

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