Here is one that I really would like to know if I have the right answers-
In data from a sample of 400 cases, a variable has a 95% confidence interval
of 54.3 to 54.7 find the following:
Mean, standard deviation and standard error.
I have come up with the following
Mean 54.5 Standard Deviation 2.04 and standard error .1020?
One more thing- could someone tell me with the large F means when you have a histogram table?
Thanks
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This is only a guess = could F stand for "frequency?"
Correct the first part! Good job!
To calculate the mean, you would take the average of the lower and upper bounds of the confidence interval. In this case, the mean would be (54.3 + 54.7) / 2 = 54.5.
To calculate the standard deviation, you would use the formula (upper bound - lower bound) / (2 * Z), where Z is the z-score corresponding to the desired confidence level. For a 95% confidence level, the z-score is approximately 1.96. So, the standard deviation would be (54.7 - 54.3) / (2 * 1.96) = 0.1 / 1.96 = 0.051.
To calculate the standard error, you would divide the standard deviation by the square root of the sample size. In this case, the sample size is 400, so the standard error would be 0.051 / √400 = 0.051 / 20 = 0.00255.
So, the correct answers are:
Mean: 54.5
Standard Deviation: 0.051
Standard Error: 0.00255.
Regarding your question about the large F on a histogram table, I'm not certain of its meaning without more context. However, in statistics, "F" typically refers to the F-distribution, which is a probability distribution that arises in the context of statistical hypothesis testing. The F-distribution is used to compare the variances of two or more samples. It is also used in analysis of variance (ANOVA) tests. So, if you see a large "F" on a histogram table, it may suggest that there are significant differences in the variances between groups or samples.