In: Statistics and Probability
(a) The probability of a defective item produced by a machine is 0.20.
Find the probability that at least 3 of the 5 next items produced by
a machine will be in this defective.
(b) Analyze skewness of the following data with formula and diagram.
1,2,5,2,3,1,3,1.
a] the probability of a defective item is , 
the probability that at least 3 of the 5 next items produced is defective is given by

number of bernoulli trials , 
failure probability , 
the probability is given by

we get


b] we have the data as
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| 1 | -1.25 | 1.5625 | -1.953125 | 
| 2 | -0.25 | 0.0625 | -0.015625 | 
| 5 | 2.75 | 7.5625 | 20.796875 | 
| 2 | -0.25 | 0.0625 | -0.015625 | 
| 3 | 0.75 | 0.5625 | 0.421875 | 
| 1 | -1.25 | 1.5625 | -1.953125 | 
| 3 | 0.75 | 0.5625 | 0.421875 | 
| 1 | -1.25 | 1.5625 | -1.953125 | 
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we get mean as

the skewness is given by

since the value is between 0.5 and 1 , we get the distribution as moderately skewed