There are 17 trees along the road from Basil's home to a swimming pool. On his way way to and from a swim Basil marks some trees
with a red stripe. On his way to the pool he marks the first, the third, the fifth tree and so on. On his way back again, he marks the first tree he comes to, the fourth tree, the seventh tree and so on, missing out two trees each time. By the time he gets home how many trees have no mark?
1 answer:
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Answer:
182.41
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
40th percentile
Value of X when Z has a pvalue of 0.4. So X when Z = -0.253.
So the answer is 182.41.