This is a relatively simple question taken from the January 2005 MS/SS1B paper that I am kind of struggling with..
4) Chopped lettuce is sold in bags nominally containing 100 grams.
The weight, X grams of chopped lettuce, delivered by the machine filling the bags, may be assumed to be normally distributed with the mean M and standard deviation 4.
b) Determine the minimum value of M so that at most 2% of the bags of chopped lettuce are underweight. Give your answer to one decimal place.
c) Boxes each contain 10 bags of chopped lettuce. The mean weight of a bag of chopped lettuce in a box is denoted by (X bar).
Given that M = 108.5
i) Write down values for the mean and variance of (X bar)
ii) Determine the probability that (X bar) exceeds 110.
Any help would be truly appreciated!
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S1 exam question: Normal distribution watch
- Thread Starter
- 16-05-2005 23:43
- 17-05-2005 03:33
The actual z-score is less than 0.5, there fore the z-value must lie to the left of the mean of the distribution.
By linear interpolation betweeen the values of z=1.96 and z=2.3263