The mean weight of the students in a school is 70 kilograms. A random sample of 25 students was taken and the mean weight was fo
und to be 55 kilograms with a standard deviation of 20 kilograms. What is the test statistics? Express your answer into 2 decimal places (example: 25.00)
1 answer:
Answer:
-3.75
Step-by-step explanation:
The question refers to the fact that we calculate the value of z in order to know how successful the random sample is in terms of probabilities:
z = (x -m) / (sd / n ^ (1/2))
where x is the value to evaluate, that is to say 55 kg, the standard deviation is sd and would be 20 kg, m is the mean that is 70 and n the size of the random sample that is 25, replacing we are left with:
z = (55 - 70) / (20/25 ^ (1/2))
z = -3.75
this value represents practically 0%, making the sampling that was made very unlikely
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