I need help

Question

Where did you get the 95 % of confidence interval to be 0.28

Answer 1

Step 1:

Its not that for 95 % confidence interval we get 0.28.

95 % confidence interval is used to calculate the value of .

The 95 % confidence interval, .

The is Z-score value for the area of the region of value .

Look into inverse standard normal distribution table.

Now the value of Z-score for is .

Consider only positive values of Z.

Hence for 95 % confidence interval is 1.96.

Similarly,

for 90 % confidence interval is 1.65.

for 98 % confidence interval is 2.33.

for 99 % confidence interval is 2.58.

Conclusion:

for 95 % confidence interval is 1.96.