Online shopping. Online shopping statistics are routinely reported by www. shop. org. Of interest to many online retailers are gender-based differences in shopping preferences and behaviors. The average monthly online expenditures are reported for males and females: Male Female n 45 45 Mean $350 $310 Standard deviation $95 $80 You suspect that male shoppers are spending more than the female shoppers. Which among the following test should you use? Group of answer choices

two sample z test
two sample pooled-t test (equal population standard deviation)
two sample t test with unequal population
standard deviation paired t test

Ahypothesis is: a the average squared deviations about the mean of a distribution of values b) an empirically testable statement that is an unproven supposition developed in order to explain phenomena a statement that asserts the status quo; that is, any change from what has been c) thought to be true is due to random sampling order da statement that is the opposite of the null hypothesis e) the error made by rejecting the null hypothesis when it is true

Complete the conditional statement. if a + 2 < b + 3, then a < b b < a a – b < 1 a < b + 1

Aprisoner is trapped in a cell containing three doors. the first door leads to a tunnel that returns him to his cell after two days of travel. the second leads to a tunnel that returns him to his cell after three days of travel. the third door leads immediately to freedom. (a) assuming that the prisoner will always select doors 1, 2 and 3 with probabili- ties 0.5,0.3,0.2 (respectively), what is the expected number of days until he reaches freedom? (b) assuming that the prisoner is always equally likely to choose among those doors that he has not used, what is the expected number of days until he reaches freedom? (in this version, if the prisoner initially tries door 1, for example, then when he returns to the cell, he will now select only from doors 2 and 3.) (c) for parts (a) and (b), find the variance of the number of days until the prisoner reaches freedom. hint for part (b): define ni to be the number of additional days the prisoner spends after initially choosing door i and returning to his cell.