Question

Consider the following: Analyzes of national data have suggested that the adult population uses social media an average of 3 hours per day, with a standard deviation of 1 hour. Develop a main response in which you address the following:

• Ask a group of friends (or other acquaintances) how many hours they spent on social media the previous day.
• Calculate the mean for this group (this is your sample mean).
• Use this value, along with the population mean and standard deviation provided above, to conduct a one-sample z-test.
• Share your z-test and the results on the discussion board.
• Explain whether or not the difference between your sample and the population is statistically significant.
• Discuss some reasons for this significant difference or lack thereof.

Time spent on social media by my group of friends in hours: 3 hrs, 7 hrs, 5hrs, 5hrs

Answer 1

Time spent on social media by a group of friends in hours: 3 hrs, 7 hrs, 5hrs, 5hrs.

Here, we are to test if the different from 3 hours. That is, we are to test:

Since, the population stadard deviation is known to be 1, the test statistic is:

Now,

Now,

At 5% level of significance, we reject iff

Now,

Hence, it is observed that,

Hence, we reject the Null Hypothesis and claim that the mean is different from 3 hrs.

Reasons for this significant difference
i) No. of samples is very less.
ii) Samples might not be random.
iii) Underlying distribution might not be Normal.

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