a teacher looks at a random sample of 42 final exam completion times and finds a mean time of 111 minutes with a sample standard deviation of 44 minutes. Which value best approximates the margin of error for a

The mean age when smokers first start is 13 years old with a population standard deviation of 1.9 years. A researcher thinks that smoking age has significantly changed since the invention of ENDS-electronic nicotine delivery systems. A survey of smokers of this generation was done to see if the mean age has changed. The sample of 31 smokers found that their mean starting age was 12 years old. Do the data support the claim at the 1% significance level? What are the correct hypotheses? Ho: LU Test Statistic z = #v Critical Values =+ O OF 13 H₁: u Based on the hypotheses, find the following: 13 o years (Round to 4 decimal places.) (Round to 2 decimal places.) Based on the above we choose to Reject the null hypothesis years The correct summary would be: There is enough evidence to support the claim smokers first start is different than 13. that the mean age

The mean age when smokers first start is 13 years old with a population standard deviation of 1.9 years. A researcher thinks that smoking age has significantly changed since the invention of ENDS- electronic nicotine delivery systems. A survey of smokers of this generation was done to see if the mean age has changed. The sample of 30 smokers found that their mean starting age was 12.2 years old. Do the data support the claim at the 1% significance level? What are the correct hypotheses? Ho: Select an answer v ? v years H3: Select an answer v years The test is: O One-tailed O Two-tailed

When computing the variance using a sample of size n = 30, we divide the sum of squared deviations by Give your answer as a whole number.

3) Last year, the mean running time for a certain type of flash light battery was 8.5 hours. This year, the manufacturer has introduced a change in the production method which he hopes will change the mean running time. A random sample of 40 of the new light bulbs was obtained and the mean running time was found to be 8.7 hours. Do the data provide sufficient evidence to conclude that the mean running time of the new light bulbs is different from last year's mean of 8.5 hours? Perform the appropriate hypothesis test using a significance level of 0.05. Assume that standard deviation of running time of all new light bulb batteries of this type is 0.5 hours.

What is the typical age of a person who renews his orher driver’s license online? From a random sample of660 driver’s license renewal transactions, the mean agewas 52.6 and the standard deviation was 6.4. Computethe 98% confidence interval estimate of the mean ageof online renewal users in this county.

Suppose that a garage samples 21 customers. They find the average time for there oil change is 4,305 miles. Find a 90% confidence interval of the true mean, if the population standard deviation is 1,151. What is the upper bound of the confidence interval? (round to the correct integer)