An article in the november 1983 consumer reports compared various types of batteries. the average lifetimes of duracell alkaline aa batteries and eveready energizer alkaline aa batteries were given as 4.1 hours and 4.5 hours, respectively. suppose these are the population average lifetimes. (a) let x be the sample average lifetime of 121 duracell and y be the sample average lifetime of 121 eveready energizer batteries. what is the mean value of x − y (i. e., where is the distribution of x − y centered)?

Shania's test scores in 8 subjects were 88, 91, 85, 74, 69, 72, 80, and 87. shania found the middle number of her scores. which type of measure did she find?

Do social recommendations increase ad effectiveness? a study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. the results are given below.correctly recalled the brandarrival 409153browsing20484b. conduct the hypothesis test, using the 0.025 level of significance.what is the value of the test statistic? χ2stat=what is the p-value? p-value=is this value significant atα=0.025?

How many times larger is 6 × 10^12 than 2 × 10^7? a. 30,000 b. 3,000 c. 3,000,000 d. 300,000