Question

How much time do you spend talking on your phone per day?

Guess the number of minutes you think you spend talking on the phone each day. This is your null hypothesis.

Secure the data from your phone for the past month and conduct a one sample hypothesis test of the mean length of your phone calls per day.   Be sure to show all your work by using excel and include your data set. Use a significance level of 0.05. You will have 30 data values showing the total of minutes you spend per day. (The easiest way to secure this data is to look at your "Recent" calls on your phone and list the total number of minutes that you have spent on the phone each day in the last 30 days. This will be the data that you will use.)

Answer 1

Solution: The data regarding the total number of minutes on phone calls per day

Number of days	total number of minutes of phone calls per day
1	23
2	32
3	17
4	20
5	43
6	60
7	5
8	31
9	36
10	53
11	90
12	87
13	6
14	13
15	14
16	23
17	25
18	26
19	30
20	38
21	40
22	51
23	42
24	10
25	11
26	8
27	6
28	25
29	23
30	40

Summary Statistics of the data

Summary Statistics regarding the data
Mean	30.93333333
Standard Error	3.918694755
Median	25.5
Mode	23
Standard Deviation	21.46357513
Sample Variance	460.6850575
Kurtosis	1.724273462
Skewness	1.25739716
Range	85
Minimum	5
Maximum	90
Sum	928
Count	30

The null hypothesis regarding the data is

H₀: µ=30,

i.e. The average number minutes spent on phone calls is 30 mins

H₁: µ≠30 (two-sided test)

i.e. The average number minutes spent on phone calls is not 30 mins

Based on the sample size n=30, we can use the normal test for single mean.

The test statistics under null hypothesis is

Z=

where is the sample mean, average number of minutes on phone calls per day

= standard error, i.e.

µ₀=30, hypothesized value, assumed number of minutes spent on the phone calls per day

Z= (30.93333333-30)/ 3.918694755

Z_calculated= 0.238174542

for 0.05 level of significance the critical values drawn from the Normal test tables  are -k=-1.96, k=1.96

For a two sided test, the criteria for accepting the null hypothesis is such that

from the above results, Z_calculated = 0.238174542 lies between -1.96 and 1.96.

Conclusion: Hence from the above study we can conclude that the average number of minutes spent talking on phone per day is 30 minutes.

Note:the above results are based on the data of my phone call duration (in minutes) per day from past 30 days ( as suggested by yourself). Results may vary for different samples.

Hope this answer helped you. Please rate the answer. Thank you.