## Conduct a hypothesis test at 5% signiﬁcance level that the population mean of Number of Tags is 425.

Writing Assignment Description For this writing assignment, you are required to analyze a given dataset, apply statistical concepts you learned in this class, and present your results in an eﬀective and professional manner. The assignment is 10% of your ﬁnal grade. Following are the rules for the assignment: • The assignment must be submitted individually. You are welcome to work in groups, but each student must submit his or her own assignment. Keep in mind that working together does not mean that you submit close replicas of each others’ work. Read the rules regarding plagiarism. If any assignment is found to be plagiarized, you will receive a grade of 0 for the assignment and disciplinary actions will be taken. • It is due on Dec 20, 2019 by 11:59 p.m. There will be absolutely NO extensions to this deadline, and late assignments will not be accepted. • You will submit two ﬁles for this assignment:
1. An Excel ﬁle that contains your calculation. 2. A Word ﬁle that contains your results, and interpretations. • You will upload your ﬁles on BlackBoard in the designated folder.
In your Word ﬁle: • Put your full name, course name, semester, and “Writing Assignment: the name of your data ﬁle” at the top of the ﬁrst page. • Use font: Times New Roman, size: 12 pts, and spacing: 1.5. • When answering each question, number each one followed by your excel results, and interpretation. Position your tables, graphs, and charts in an organized way. Graphs should have proper titles, axis labels, legends (if applicable) and should be easy to read. • This ﬁle must NOT exceed 3 pages. • Name your word ﬁle as “Lastname Firstname Result 221”.
In your Excel ﬁle: • Show all your calculations. You can use diﬀerent worksheets in the same Excel ﬁle. • Name your ﬁle as “Latsname Firstname Calculation 221”.
1
Using the dataset “02FacebookFriends”, answer the following questions:
1. Find the mean, median, sample variance and sample standard deviation for the variables Age and Number of Tags.
2. Create a histogram using Excel’s Data Analysis toolpack for Number of Tags. Use the Sturges’ rule to ﬁnd how many bins you should include. In your Word ﬁle, make sure to include both a frequency table for the histogram with bin limits, frequencies and relative frequencies, and your histogram chart. What can you say about the distribution of Number of Tags?
3. Do a scatterplot with X = Age and Y = Number of Tags. Interpret the plot.
4. Find the covariance and correlation coeﬃcient between Number of Tags and Age. Explain what these statistics mean for your dataset.
5. Conduct a hypothesis test at 5% signiﬁcance level that the population mean of Number of Tags is 425:
(a) Assume that the dataset given is a sample and population standard deviation is unknown.
6. Calculate the conﬁdence interval for population mean of Number of Tags for 90%, 95%, and 99% conﬁdence levels:
(a) Assume that the dataset given is a sample and population standard deviation is unknown.
7. Can you reject the hypothesis that the population mean of Number of Tags is 425 in both questions 5a and 6a?