Answer:
A matched-pairs hypothesis test for μD
Step-by-step explanation:
The trainer wants to compare each athlete's time before the program to the time after the program. Since we're comparing times for the same athlete, the data is paired, so we should use a matched-pairs test.
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Answer:
3.84% probability that it has a low birth weight
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:

If we randomly select a baby, what is the probability that it has a low birth weight?
This is the pvalue of Z when X = 2500. So



has a pvalue of 0.0384
3.84% probability that it has a low birth weight