# Study Giude for Business Statistics

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41. Whenever the population standard deviation is unknown, which distribution is used in developing an interval estimate for a population mean? d. t distribution

42. The t distribution should be used wheneve b. the sample standard deviation is used to estimate the population standard deviation

43. Whenever using the t distribution in interval estimation, we must assume that the b. degrees of freedom equals n − 1

44. From a population that is normally distributed with an unknown standard deviation, a sample of 25 elements is selected. For the interval estimation of (, the proper distribution to use is the d. t distribution with 24 degrees of freedom

45. From a population that is not normally distributed and whose standard deviation is not known, a sample of 50 items is selected to develop an interval estimate for (. Which of the following statements is true? c. The t distribution with 49 degrees of freedom must be used.

46. As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution b. becomes smaller

47. The t value with a 95% confidence and 24 degrees of freedom is b. 2.064

48. A sample of 26 elements from a normally distributed population is selected. The sample mean is 10