We calculated the 99% confidence interval for the average age of runners in the 2014 London...
We calculated the 99% confidence interval for the average age of runners in the 2014 London Marathon as (263.5237, 283.472) based on a sample of 100 runners. How could we decrease the width of this interval without losing confidence?
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We calculated the 99% confidence interval for the average age of
runners in the 2014 London...
3. Age of runners. The average of the runners’ ages is µ = 34.05 years with...
3. Age of runners. The average of the runners’ ages is µ = 34.05 years with a standard deviation of σ = 9.83. A simple random sample of 100 runners is taken. a. Find the standard deviation of the sample mean, σx. b. In your opinion, would you be surprised to get a sample (of size 100) with an average age of 36 years? Why or why not? (One idea: start by calculated this probability, the probability of getting an...
(1 point) Suppose we want a 99% confidence interval for the average amount spent on books...
(1 point) Suppose we want a 99% confidence interval for the average amount spent on books by freshmen in their first year at college. The amount spent has a normal distribution with standard deviation $30. How large should the sample be if the margin of error is to be less than $4? ANSWER:
QUESTION 21 If we change a 90% confidence interval estimate to a 99% confidence interval estimate...
QUESTION 21 If we change a 90% confidence interval estimate to a 99% confidence interval estimate while holding sample size constant, we can expect a. the width of the confidence interval to increase. b. the width of the confidence interval to decrease. c. the width of the confidence interval to remain the same. d. the sample size to increase. QUESTION 22 Which one of the following is a correct statement about the probability distribution of a t random variable? a....
Question 7 (1 point) The owner of a local golf course wants to determine the average...
Question 7 (1 point) The owner of a local golf course wants to determine the average age of the golfers that play on the course in relation to the average age in the area. According to the most recent census, the town has an average age of 55.89. In a random sample of 30 golfers that visited his course, the sample mean was 45.84 and the standard deviation was 6.514. Using this information, the owner calculated the confidence interval of...
aminate sheets under specified conditions was calculated as 5.81 695 A 95% CI for true average mount of war age mm o warpage is normally distributed. ased on a sample size and the as surm on that amo...
aminate sheets under specified conditions was calculated as 5.81 695 A 95% CI for true average mount of war age mm o warpage is normally distributed. ased on a sample size and the as surm on that amount r n (a) Suppose you want to test H0: μ-7 versus Ha: μ 7 using α = 0.05. what conclusion would be appropriate, and why? since the null value o 7 is in the 95% confidence interval we re ect 0 There...
For confidence interval computations, if the sample size is increased, we expect the margin of error...
For confidence interval computations, if the sample size is increased, we expect the margin of error to: a. Increase b. Decrease c. stay the same The company you work for produces automotive parts for GM. A certain machine that makes a cutout in a piece of steel averages a cut size of 203.2085 mm with a standard deviation of 0.2083 mm. A random sample of 66 is taken from the population. What is the distribution of the sample mean? Approximately...
We would like to estimate the true average age of customers for a particular company. How...
We would like to estimate the true average age of customers for a particular company. How large would the sample size need to be for the margin of error (based on 95% confidence) to be 1 year? Suppose that, based on previous research, we can assume the standard deviation of customer ages will be 14. Select one: a. 3872 b. 784 C. 753 X d. 659
Suppose a survey of 2,718 medical school interns found their average age to be 28.0 years,...
Suppose a survey of 2,718 medical school interns found their average age to be 28.0 years, with standard deviation 3.7 years. (a) The distribution of ages is not normal. Will the distribution of sample mean, x, have an approximate normal shape? Yes No (b) If we standardize with sample standard deviation s instead of population standard deviation o, will the standardized sample mean follow an approximate z distribution? Yes No (c) Report an approximate 95% confidence interval for population mean...
Question 1 (1 point) A customer wants to estimate the average delivery time of a pizza...
Question 1 (1 point) A customer wants to estimate the average delivery time of a pizza from the local pizza parlor. Over the course of a few months, the customer orders 29 pizzas and records the delivery times. The average delivery time is 23.69 with a standard deviation of 7.212. If the customer estimates the time using a 95% confidence interval, what is the margin of error? Question 1 options: 1) 0.7137 2) 2.2782 3) 2.7433 4) 1.3392 5) 2.739...
QUESTION 3: For this question we will analyze data from the 2014 American Time Use Survey. The su...
QUESTION 3: For this question we will analyze data from the 2014 American Time Use Survey. The survey offers the most detailed, up-to-date portrait of how people in the United States spend their time it also offers some insight into how Americans exercise and eat. I have included all the information you need to answer this question without your needing to access the data yourself (although it is publicly available). The data are drawn from a sample of n= 11,592...
(1 point) Suppose we want a 99% confidence interval for the average amount spent on books by freshmen in their first year at college. The amount spent has a normal distribution with standard deviation $30. How large should the sample be if the margin of error is to be less than $4? ANSWER:
aminate sheets under specified conditions was calculated as 5.81 695 A 95% CI for true average mount of war age mm o warpage is normally distributed. ased on a sample size and the as surm on that amount r n (a) Suppose you want to test H0: μ-7 versus Ha: μ 7 using α = 0.05. what conclusion would be appropriate, and why? since the null value o 7 is in the 95% confidence interval we re ect 0 There...
We would like to estimate the true average age of customers for a particular company. How large would the sample size need to be for the margin of error (based on 95% confidence) to be 1 year? Suppose that, based on previous research, we can assume the standard deviation of customer ages will be 14. Select one: a. 3872 b. 784 C. 753 X d. 659
Suppose a survey of 2,718 medical school interns found their average age to be 28.0 years, with standard deviation 3.7 years. (a) The distribution of ages is not normal. Will the distribution of sample mean, x, have an approximate normal shape? Yes No (b) If we standardize with sample standard deviation s instead of population standard deviation o, will the standardized sample mean follow an approximate z distribution? Yes No (c) Report an approximate 95% confidence interval for population mean...
QUESTION 3: For this question we will analyze data from the 2014 American Time Use Survey. The survey offers the most detailed, up-to-date portrait of how people in the United States spend their time it also offers some insight into how Americans exercise and eat. I have included all the information you need to answer this question without your needing to access the data yourself (although it is publicly available). The data are drawn from a sample of n= 11,592...
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