QUESTION 10 5 points + Sa Find the critical value \( t_{C} \) for a \( 98 \% \) confidence level when the sample size is 20 . Use Table 4 on page A10 (Appendix). A. 2.528 B. 2.539 C. 1.328 D. 1.325 QUESTION 11 10 points Save Answe Assume that IQ scores are normally distributed with a mean of 100 and a standard deviation of 15 . If a sample of 70 people are selected, find the probability that the mean IQ score of the sample is greater than 102. A. 0.447 B. 0.132 C. 0.868 D. 0.553 Click Save and Submit to save and submit. Click Save All Answers to save all answers. Save All Answers Save and Submit here to search

Step 1 ：\(\text{For question 10}:\)

Step 2 ：\(\text{Step 1: Determine the degrees of freedom: } df = n - 1 = 20 - 1 = 19 \)

Step 3 ：\(\text{Step 2: Look up the critical value in the t-table for } df = 19 \text{ and } 98\% \text{ confidence level: } t_{C} = 2.539 \)

Step 4 ：\(\text{Answer 10:} 2.539\)

Step 5 ：\(\text{For question 11}:\)

Step 6 ：\(\text{Step 1: Calculate the standard error: } SE = \frac{\sigma}{\sqrt{n}} = \frac{15}{\sqrt{70}} \approx 1.7894 \)

Step 7 ：\(\text{Step 2: Calculate the z-score for the sample mean: } z = \frac{\bar{x} - \mu}{SE} = \frac{102 - 100}{1.7894} \approx 1.1174 \)

Step 8 ：\(\text{Step 3: Find the probability using the z-table that z-score is greater than 1.1174: } P(z > 1.1174) \approx 0.1319 \)

Step 9 ：\(\text{Answer 11:} 0.1319\)