If the desired precision to estimate a mean is increased by a ...

[TFauchery]

If the desired precision to estimate a mean is increased by a factor of four (for example, from 40 to 10) the sample size is increased by a factor of __________, all else equal.
 a. 30.0
  b. 4.0
  c. 16.0
  d. 2.0
  e. 32.0

Question 2

Two standard deviations about the mean of a normal distribution include approximately __________ of all observations.
 a. 90
  b. 95
  c. 99
  d. Can't say; it depends on the individual sample variance.
  e. Can't say; it depends on the size of the population.

[emily12345]

Answer to Question 1

C

Answer to Question 2

b