a. If z-score of a normal distribution is 2.5, the mean of the distribution is 45 and the standard deviation of the normal distribution is 3 then the value ofyfor a normal distribution is?(Round your answer to 2 decimal places.)

b.The morning sales at a small coffee house are normally distributed with a mean of $600 and a standard deviation of $60. What is the z-value for a $540 morning of sales?

c.A survey of 25 grocery stores revealed that the average price of a 4-litre bag of milk was $3.48 with a standard error of $0.20. What is the 95% confidence interval to estimate the true cost of a 4-litre bag of milk? ( t table)

Income tax returns in Canada in 2018 averaged $1532 in refunds for taxpayers with the standard deviation of $925. The amounts owed or due on tax returns are normally distributed.

a. What proportion of the tax returns shows a refund of more than $1800?

b. What proportion of the tax returns shows a refund between $700 and $1300?

c. What amount of the tax refund should a person receive to be in the top 5% of the distribution?