SOLUTION: Question 3
Many people believe that the average number of Facebook friends is 338. The population standard deviation is 43.2. A random sample of 50 high school students in a count
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Many people believe that the average number of Facebook friends is 338. The population standard deviation is 43.2. A random sample of 50 high school students in a count
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Question 1183829: Question 3
Many people believe that the average number of Facebook friends is 338. The population standard deviation is 43.2. A random sample of 50 high school students in a country revealed that the average number of Facebook friends was 350. At α = 0.05,
a. Why was the sample collected?
b. Calculate the significant level for this hypothesis test.
c. Find the critical value for this test at α = 0.05.
d. Calculate the test value.
e. Based on the test value and the critical value is there enough evidence to conclude that the mean number of friends is greater than 338?
f. Determine whether it is a one - tail or a two - tail test.
g. Find the maximum error E for estimating population mean. Answer by robertb(5830) (Show Source):
You can put this solution on YOUR website! a. The sample was collected to determine whether the belief that the average number of Facebook friends of 338 is still true.
b. The signicance level is , no need to calculate. (But do you know what this value means?)
c. By the CLT, the sampling distribution of the sample means is approximately normally distributed with mean , and standard dev .
===> critical value for a ONE-TAILED test (will explain later why) is 1.645.
d.
e. By comparing the test value with the critical z, we reject the null hypothesis, and conclude that
there is evidence that the average number of Facebook friends may have increased from 338.
f. It is a one-tailed test because the sample value of 350 is quite far from 338 (on the high side), enough to suspect that the
true sample mean may have increased from 338.
