1) Find the z-score(s) for which 90%of the distribution's area lies between -z and z. (round to the nearest thousandth)

2) Find the area under the standard normal.

(a) to the right of z =1.

(b) right of z = -1.50and to the left of z =2.50

3) Suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000.Find the percentage of buyers who paid:

between $150,000and $155,400if the standard deviation is $1800.

4) A random variable x is normally distributed with =60. Convert the value of x to a z-score, if the standard deviation is as given.

(a) x=60 and =60

(b) x=30 and =8

6) Find the critical value Z_/2that corresponds to a 91%confidence level

7) Find the sampleneeded to estimate the percentage of Republicans among registered voters in California. Use a 0.03 margin error, use the confidence level of 90%, and assume that p-hat and q-hat are unknown.

8) Find the sampleneeded to estimate the percentage of Democrats who have tattoos.Use a 0.05margin error, use the confidence level of 99%, and use results from a prior Harris poll suggesting that 15%of Democrats have tattoos.

9) In a randomized controlled trial in Kenya, insecticide treated bednetswere tested as a way to reduce malaria. Among 343 infants using bednets, 15 developed malaria. Among 294 infants not using bednets, 27 developed malaria. Want to use a 0.01 significance level to test the claim that the incidence of malaria is lower for infants using bednets. Find the test statistic.

10) In a randomized controlled trial in Kenya, insecticide treated bednetswere tested as a way to reduce malaria. Among 343 infants using bednets, 15 developed malaria. Among 294 infants not using bednets, 27 developed malaria. Want to test the claim that the incidence of malaria is lower for infants using bednets. Construct a 99% confidence interval.