Eric is studying people's typing habits. he surveyed 525 people and asked whether they leave one space or two spaces after a period when typing. 440 people responded that they leave one space. create a 90% confidence interval for the proportion of people who leave one space after a period.

Step-by-step explanation:

The confidence interval for population proportion (p) is given by :_

, where n= sample size

z* = Critical value.

= Sample proportion.

Let p  be the true population proportion of people who leave one space after a period.

As per given , we have

n= 525

By z-table , the critical value for 90% confidence interval : z* = 1.645

Now , 90% confidence interval for the proportion of people who leave one space after a period:

Hence, a 90% confidence interval for the proportion of people who leave one space after a period.

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490

the answer is b