A study showed that in a certain month, the mean time spent per
visit to Facebook was 19.5 minutes. Assume the standard deviation
of the population is 8 minutes. Suppose that a simple random sample
of 100 visits in that month has a sample mean of 21.66 minutes. A
social scientist is interested in knowing whether the mean time of
Facebook visits has increased. Perform the hypothesis test and
compute the P-value.
Write down your P-value. You will need it for the next
question.
Round your answer to four decimal places (for example: 0.2305).
Write only a number as your answer.
Ho : = 19.5
H1 : > 19.5
Test statistic Z
Z = ( xbar - )/(/√n)
Z = ( 21.66 -19.5)/(8/√100)
Z = 2.70
p-value for Z = 2.70 and right tailed test
p-value = P( Z > 2.70)
p-value = 0.0035
Here p-value = 0.0035 < 0.05
Decision : We reject the null hypothesis
Conclusion : There is sufficient evidence to support the claim that the mean time of Facebook visits has increased.
p-value = 0.0035
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