3- Based on their blood samples, 900 COVID-19 seroprevalence Canadian were randomly selected and 360 of them never experienced any symptoms. A patient is COVID-19 seroprevalence if they have been exposed to the virus.

(A) construct a 95% confidence interval to capture the true value of the proportion of the Canadians who are COVID-19 seroprevalence, but they were asymptomatic.

(B) Does the data support the hypothesis that the true proportion of the asymptomatic COVID-19 seroprevalence patients in Canada is less than 30%. Compute the P-value for the test and make a conclusion by comparing your P-value to 5%. Make sure you state your null and alternative hypotheses.

4- In a Department store a random sample of 600 customers were followed when shopping and it was observed that 110 of them asked staff members to help them locate items in the aisles. Then, the store spent $100,000 to install larger signs on the aisles with a list of items printed in a larger font. After implementing the change, they randomly followed 500 customers and observed that 70 of them asked the staff to help them locate items.

Did spending $100,000 paid off in terms of reducing the proportion of customers not being able to locate items without the help of staff. Use = 0.05 to draw a conclusion. Make sure you state your null and alternative hypotheses.