Question

Construct a 93% confidence interval for the sample labelled “problem 3” in the data sheet. What is the probability that the population mean might be outside the interval?

108
159
131
154
96
110
106
73
74
138
108
83
211
97
110
93
55
64
108
118
128
83
131
136
74
90
133
182
128
97
124
135
135
106
120
199
159
132
189
95
126
176
112
130
179
122
159
109
141
139
138
170
121
143
90

Answer 1

Dear student, please comment in the case of any doubt and I would love to clarify it.  

To find out the confidence interval, we will be using excel. Excel has a data analysis option named as descriptive statistics.

Steps for getting descriptive Analysis -

1. On the Data tab, in the Analysis group, click Data Analysis and select confidence interval and write 93% there.

2. Select Descriptive Statistics and click OK.

3. Select the range input values as the Input Range.

4. Select any cell for output as the Output Range.

5. Make sure Summary statistics are checked.

The confidence interval will be calculated by using (mean - CI) and (mean+CI)

Here mean comes out to be 124.1273 whereas CI comes to be 8.52

Hence the interval will be (124.1273 - 8.52) to (124.1273 + 8.52), which is 115.6072 to 132.6473.