Anonymous
Anonymous asked in Science & MathematicsMathematics · 4 weeks ago

Can someone help me with my Math work ?

The weights of ice cream cartons are normally distributed with a mean weight of 11 ounces and a standard deviation of  0.5 ounce. 

​(a) What is the probability that a randomly selected carton has a weight greater than 11.22 ​ounces? Round to 4 decimal places

​(b) A sample of 25 cartons is randomly selected. What is the probability that their mean weight is greater than 11.22 ​ounces? Round to four decimal places

 

1 Answer

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  • 4 weeks ago

    a) the z-score is ( 11.22 - 11)/.5 = .44

       Pr( X > .44 ) =  .33

      ( using a normal prob calculator http://onlinestatbook.com/2/calculators/normal_dis... )

    b)  mean of the sample is normally with mean = 11 and std dev of .5/sqrt(25) = .1

         

          z score = ( 11.22 - 11)/.1 = 2.2 

         So prob that the mean of a random sample is prob that a sttandared normal variate exceeds 2.2  =   .0132

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