Question
i need help with Q#1 and #3. please.
Take Test: 63 Online Ho x The Average Teacher's S X | Secure l 341_1&course;_id-45012-1&content-id-2591840-1;&step;=null ty of Texas Rio Grande Valley a Lynda Ros Remaining Time: 27 minutes, 50 seconds. MyCourses Question Completion Status QUESTION 1 1 points Save AnsweY The average teachers salary in X-city is $37,230. Assume a normally distribution with standarod deviation of the population of $5,100. For a sample of 75 teachers, what is the probability that the sample mean is greater than $38,000? O 0.1245 04521 0.9066 O 00934 QUESTION 2 1 points Saved In order to have the standard error of the mean be 12, one would need to take normally distributed population with a standard deviation of 24 samples from a 16 QUESTION 3 1 points Save Answer The mean weight of loads of rock is 500 tons with a standard deviaton of 8.0 tons. It 9 loads are chosen at random for a weight check, find the probability that the mean weight of those loads is less than 49.1 tons Assume that the variable is normally distributed O13.68 3632 63.68 86.32 QUESTION 4 1 points ai Sprert
Explanation / Answer
1)
mean = 37230 , s = 5100 , n =75
P(X > 38000)
z = ( x - mean)/(s/sqrt(n))
= ( 38000 - 37230)/(5100/sqrt(75))
= 1.3075
P(X > 38000) = P(z > 1.3075) = 0.0934
3)
mean = 50 , s = 8 , n= 9
P(X < 49.1)
z = (x - mean)/(s/sqrt(n))
= ( 49.1 - 50)/(8/sqrt(9))
= -0.3375
P(X < 49.1) = P(Z < -0.3375) = 36.32
