Find z if the standard normal curve area between – z and z is 0.4530.

Step-by-step explanation:

Hi,

1) Find z if the standard normal curve area between -z and z is 0.4530.

Y1 = normalcdf(-x,x,0,1) - .4530 and x = .60226

a. ± 0.118

b. ± 0.398

c. ± 0.602 <==ANSWER

d. ± 0.752

2) If a random variable has the normal distribution with μ = 104.3 and σ = 5.7, find the probability that the value will be greater than 112.3

normalcdf(112.3, 500, 104.3, 5.7) = .08023

a. 0.08 <==ANSWER

b. 0.09

c. 0.10

d. 0.11

3) Determine a 90% confidence interval for μ if σ = 5, \bar{x} = 70, and n = 82. Answer interval rounded to two decimal places.

70 ± 1.645 (5/√82) or 69.09 to 70.91 <==ANSWER

I hope that helps!! :-)

correct answers below:

4a. is 3 miles every hour

4b. is 1/3 of an hour per mile

step-by-step explanation: