The confidence interval is from 0.2191 to 0.2649, given by
.
The z-score we need is found by first subtracting the confidence level from 1:
1 - 0.95 = 0.05
Divide that by 2:
0.05/2 = 0.025
Subtract that from 1:
1 - 0.025 = 0.975
Look this up in the middle of a z-table (http://www.z-table.com) and we see that the z-score is 1.96.
Now our confidence interval is given by
The z-score we need is found by first subtracting the confidence level from 1:
1 - 0.95 = 0.05
Divide that by 2:
0.05/2 = 0.025
Subtract that from 1:
1 - 0.025 = 0.975
Look this up in the middle of a z-table (http://www.z-table.com) and we see that the z-score is 1.96.
Now our confidence interval is given by