When is a t-test used instead of a z-test? a When the population deals with two samples b. When the population μ is known c. When the population standard deviation is unknown d. When the population s

What is the value of SS (sum of squared deviations) for the following set of scores? If the scores constitute a population, what is the population standard deviation, s?  Scores: 1, 1, 4, 0.​

When using 1-Var Stats on a scientific or graphing calculator, the resulting statistical output includes two values for the standard deviation of the data set.  These values are labeled as Sxand σx in the statistical output.  Why is it necessary to give two values for the standard deviation?  How would you choose which one to use as the standard deviation of a data set you are working with?  Be sure to explain the difference between these two values as you answer these questions

A new material will replace the old material only if there is significant evidence that the mean strength of the new material is more than 2 units higher than the mean strength of the old material.        Sample from new material:     mean  is  98.064   ,     SD  is   5.6     and sample size is 13 Sample from old material:       mean  is  95.282   ,     SD  is   5.8      and sample size is 78 We do not know population standard deviations. Consider the test           ?0:????−????=2H0:μnew−μold=2   vs.  ?0:????−????>2H0:μnew−μold>2  What is the p-value?       (Hint:  best to use software, or else the Desmos Calculator for the 2 sample T and Z test)  Give as a decimal between 0 and 1 accurate to at least 4 decimal places.

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Claim: The standard deviation of pulse rates of adult males is more than 12 bpm. For a random sample of 172 adult​ males, the pulse rates have a standard deviation of 11.5 bpm. Find the value of the test statistic?

Chebyshev's Theorem states that for any distribution of numerical data, at least 1-1/k? of the numbers lie within The percent of numbers between 88 and 112 is at least %. k standard deviations of the mean. (Round to the nearest hundredth as needed.) In a certain distribution of numbers, the mean is 100, with a standard deviation of 6. Use Chebyshev's Theorem to tell what percent of the numbers are between 88 and 112.

IQ is normally distributed with a mean of 100 and a standard deviation of 15. Suppose one individual is randomly chosen. Let X = IQ of an individual. The middle 30% fall between what two values? (round to 2 decimal places)

he average amount of time boys and girls  spend playing sports each week is believed to be the same. A sample of equal size n is taken from boys and girls , the mean of the boys is 29 hours  with standard deviation 4  hours and the mean of the girls  is 27 hours with standard deviation 3 hours Both populations have a normal distribution. The calculated value is  1.2       n =

P and A are independent, random variables. mean of P is 5 and its standard deviation is 3. mean of A is -2 and standard deviation is 6. what is mean of T= - 3P + 20 ? what is the mean of W= A - P? what is variance of D= P - 2A ?