7/23/2019 Stats 10 Percent Test

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1) Given a normal distribution with μ = 104 and σ = 10, and given you selecta sample of n = 4

a) !hat is the probability that "bar is less than #4$ 00%%&b) !hat is the probability that "bar is between #4 and #4'$ 000'#c) !hat is the probability that "bar is above 10'($ 0*4'

%) +he following data represents the responses - for yes and . for no) froma sample of %0 college students to the /uestion o you currently own sharesin any stoc2s$3. . . . - . - - - - . . - . - . - . - .

a) etermine the sample proportion, p, of college students who ownshares of stoc2 04'

b) f the population proportion is 040, determine the standard error of the proportion 010#'

) n a recent survey of full5time wor2ers, 4&6 said that they would rathergive up some of their salary for more personal time 7uppose you select asample of 100 full5time female wor2ers

a) !hat is the probability that in the sample, fewer than '(6 wouldrather give up some of their salary for more personal time$ 0#4'

b) !hat is the probability that in the sample, between 46 and '(6would rather give up some of their salary for more personal time$ 0*&('

c) !hat is the probability that in the sample, more than 46 wouldrather give up some of their salary for more personal time$ 0&41

4) f "bar = 14(, σ = %0, and n = 4, construct a ##6 confidence intervalestimate of the population mean, μ 1*1' to 1'4&'

') +he manager of a paint supply store wants to estimate the actual amountof paint contained in 15gallon cans purchased nationally 2nown manufacturer

 +he manager8s speci9cations state that the standard deviation of the amountof paint is e/ual tp 00 gallon : random sample of '0 cans is selected, andthe sample mean amount of paint per 15gallon can is 0##1 gallon

a) ;onstruct a ##6 con9dence interval estimate for the population meanamount of paint included in a 15gallon can 0#&00* to 1001#

() f "bar = *%, 7 = # and n = 4#, and assuming that the population isnormally distributed, construct a ##6 con9dence interval estimate of thepopulation mean, μ (&'' to *'4'

*) f n = 400 and " = 100, construct a #'6 con9dence interval estimate of the population proportion 0%0*( to 0%#%4

&) +he /uality5control manager at a light bulb factory needs to determinewhether the mean life of a large shipment of light bulbs is e/ual to && hours

 +he population standard deviation is 10& hours : random sample of &1 lightbulbs indicates a sample mean life of '& hours :t the 00' level of signi9cance, is there evidence that the mean life is di<erent from && hours$μ = &&, μ does not e/ual &&, score = 5%' ;> = 1#( re?ect