If the population standard deviation is sigma= 10, how large  a sample is necessary to have a standard error that is  A) less than 5 pointa? B) less than 2 points? C) less than 1 point?

At a college the scores on the chemistry final exam are approximately normally distributed, with a mean of 73 and a standard deviation of 11. The scores on the calculus final are also approximately normally distributed, with a mean of 78 and a standard deviation of 12. A student scored 79 on the chemistry final and 81 on the calculus final. Relative to the students in each respective class, in which subject did the student do better? a) Calculus b) There is no basis for comparison c) Chemistry d) The student did equally well in each course e) None of the above

The standard deviation of the distribution of sample means would be equal to:

Most people think that the​ "normal" adult body temperature is 98.6°F. In a more recent​ study, researchers reported that a more accurate figure may be 98.1°F. ​Furthermore, the standard deviation appeared to be around 0.7°F. Assume that a Normal model is appropriate.   b) What fraction of people would be expected to have body temperatures above 98.6°​F?