QUESTION 12
Find the critical value \( t_{C} \) for a \( 99 \% \) confidence level when the sample size is 23
A. 2.074
B. 2.069
C. 2.819
D. 2.807
QUESTION 13
An economist found that a random sample of 45 high school teachers had an average annual salary of \( \$ 58,230 \). A previous study st Standard deviation is \( \$ 4450 \). Calculate the margin of error, E, for a \( 90 \% \) confidence interval for \( \mu \), the average annual salary of all hig
B. \( \$ 1091.2 \)
C. \( \$ 1300.2 \)
D. \( \$ 1652.1 \)
QUESTION 14
Let \( x \) be a random variable that represents the commute time of teachers in a large urban area. If \( x \) is normally distributed with a mean of standard deviation of 5.2 minutes, find the commute time which is at the top of the bottom \( 10 \% \).
A. 41.38 minutes
B. 42.63 minutes
C. 42.34 minutes
D. 55.66 minutes
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Answer
\(x = 42.63 \; \text{minutes} \)
Step 1 ：\(t_{C} = 2.807 \)
Step 2 ：\(E = \$ 1091.2 \)
Step 3 ：\(x = 42.63 \; \text{minutes} \)
