MATH302 Questions and Answers | Latest Update | Graded A+

MATH302 Questions and Answers | Latest Update | Graded A+ If 50 identical batteries are tested and each has a 0.70 probability of still working after 8 hours, what is the probability that more than 40 batteries will last at least 8 hours? - 0.0402 In a mathematics exam with scores normally distributed, mean of 65, and standard deviation of 15, what score corresponds to the 70th percentile? - 0.5 What happens to a confidence interval if the sample size increases from 25 to 50? - It becomes smaller For calculating sample size for a proportion, what is a conservative estimate for the population proportion ( p )? - 0.50 If other factors remain constant, how does the required sample size change when the confidence level decreases for the same margin of error? - It decreases Which confidence level results in the narrowest margin of error? - 80% A researcher finds a 95% confidence interval for the average commute time to be (15.75, 28.25). What is the correct interpretation of this interval? - We are 95% confident that the interval 15.75 < μ < 28.25 contains the population mean commute time in minutes using public transportation. A marketing company calculates a 92% confidence interval for the proportion of customers who click on smartphone ads as (0.48, 0.54). What is the correct interpretation of this interval? - We are 92% confident that the true proportion of customers who click on ads on their smartphones is between 0.48 and 0.54. If the FDA allows up to 0.82 ppm of mercury in Albacore tuna, and a laboratory wants to estimate mercury levels within 0.03 ppm with 95% confidence and a standard deviation of 0.138 ppm, what sample size is needed? (Round up to the nearest whole number.) - 82 How can the margin of error be reduced if other factors remain constant? (Select all that apply) - Decreasing the confidence level - Increasing the sample size What is the upper limit of the 90% confidence interval for a population proportion ( p ), given ( n = 100 ) and ( hat{p} = 0.20 )? - 0.2658 In a random sample of 200 people, 135 reported watching educational TV. What is the 95% confidence interval for the true proportion of people who watched educational TV? - 0.6101 < p < 0.7399