1.You'll often hear the expression, "This is accurate to plus or minus two standard deviations." Assuming that the population (or sample) has a normal distribution, what percentage of the population (or sample) is included in the quantity, "Plus or minus two standard deviations"? Be precise! (5)0.1%(pg.48 - Figure 3.2)"Probability distributions are commonly classified as continuous, meaning the data can take any value within a specific range, or discrete, meaning the data can take only a certain value." (pg. 47) "The normal distribution with a mean of 0 and standard deviation of 1." The total area under the curve is 1 and it can range from negative infinity to positive infinity. (pg. 47 - 48) Standard error depends on sample size which affects the standard deviation. Standard deviation is the square root of the variance and squared deviations are always positive. The variance requires dividing n - 1 and the variance will always be equal to or greater than 0. "Standard error is estimated by using the standard deviation divided by the square root of n." (pg. 467)