Question

qnorm(.975) [1] 1.959964 qnorm(.95) [1] 1.644854 qnorm(.90) [1] 1.281552 qnorm(.995) [1] 2.575829 (please explain the use of these qnorms and why they are present) Spring break can be a very expensive holiday. A sample of 80 students is surveyed, and the average amount spent by students on travel is $593, and the sample standard deviation is $360. (a) Construct an approximate 90% confidence interval for the population mean amount of money spent. (b) How about an approximate 95% CI? (c) For a given standard error, a 95% confidence interval will be wider than a 90% confidence interval. (True or False)

          qnorm(.975)
[1] 1.959964

qnorm(.95)
[1] 1.644854

qnorm(.90)
[1] 1.281552

qnorm(.995)
[1] 2.575829

(please explain the use of these qnorms and why they are present)

Spring break can be a very expensive holiday. A sample of 80 students is surveyed, and the average amount spent by students on travel is $593, and the sample standard deviation is $360.

(a) Construct an approximate 90% confidence interval for the population mean amount of money spent.

(b) How about an approximate 95% CI?

(c) For a given standard error, a 95% confidence interval will be wider than a 90% confidence interval. (True or False)

Show more…

Added by Emily N.

Elementary Statistics a Step by Step Approach

Allan G. Bluman 9th Edition

Instant Answer

Solved by Expert Jerelyn Nevil

08/18/2023

Step 1

Step 1: Calculate the margin of error for the confidence intervals using the formula: margin of error = z * (standard deviation / sqrt(sample size)), where z is the critical value from the standard normal distribution. Show more…

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qnorm(.975) [1] 1.959964 qnorm(.95) [1] 1.644854 qnorm(.90) [1] 1.281552 qnorm(.995) [1] 2.575829 (please explain the use of these qnorms and why they are present) Spring break can be a very expensive holiday. A sample of 80 students is surveyed, and the average amount spent by students on travel is $593, and the sample standard deviation is $360. (a) Construct an approximate 90% confidence interval for the population mean amount of money spent. (b) How about an approximate 95% CI? (c) For a given standard error, a 95% confidence interval will be wider than a 90% confidence interval. (True or False)

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