The following data represent the age (in weeks) at which babies first crawl base

Question

The following data represent the age (in weeks) at which babies first crawl based on a survey of 12 mothers (a) Because the sample we is small we must verify that the data come from population that is normality distributed and that the sample see does not any outliers Are the conditions for constructing a confidence interval about the mean satisfied? A. No, the sample contains an outlier B. No the population is not normally distributed C. Yes the population is normally, distributed and the sample does not contain any outliers (b) Construct a 95% confidence interval for the mean age at which a baby first crawls Select the correct chore below and in any answer boxes r your B. A 95% confidence interval cannot be constructed (c) What could be done to increase the accuracy of the interval without changing the level of confidence? A. Nothing can be done B. Either increase or decrease the sample size C. increase the sample size D. Decrease the sample size.

Explanation / Answer

a) as all the points are closely bound to normality curve;

option C is correct; Yes the population.....

b)

from above for (n-1=11) degree of freedom and 95% CI, t=2.201

hence 95% confidence interval =sample mean -/+ t*Std error =33.0 ; 45.0

c)

option C is correct ; increase the sample size.

X 52 30 44 35 47 37 56 26 39 39 37 26 mean(X) 39.000 std deviation(S) 9.487 std error =S/(n)1/2 2.739

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