Calculator question.
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Answer: 0.0228
Step-by-step explanation:
Given : The mean and the standard deviation of finish times (in minutes) for this event are respectively as :-
If the distribution of finish times is approximately bell-shaped and symmetric, then it must be normally distributed.
Let X be the random variable that represents the finish times for this event.
z score :
Now, the probability of runners who finish in under 19 minutes by using standard normal distribution table :-
Hence, the approximate proportion of runners who finish in under 19 minutes = 0.0228
Answer:
a. For n=25, the mean and standard deviation of the prices of the mobile homes all possible sample mean prices are $63,800 and $1,580, respectively.
b. For n=50, the mean and standard deviation of the prices of the mobile homes all possible sample mean prices are $63,800 and $1,117, respectively.
Step-by-step explanation:
In this case, for each sample size, we have a sampling distribution (a distribution for the population of sample means), with the following parameters:
For n=25 we have:
The spread of the sampling distribution is always smaller than the population spread of the individuals. The spread is smaller as the sample size increase.
This has the implication that is expected to have more precision in the estimation of the population mean when we use bigger samples than smaller ones.
If n=50, we have: