nd the standard deviation. (Enter an exact number as an integer, fraction, or decimal.) x P(x) x*P(x) (x − ?)2P(x) 2 0.1 2(0.1) = 0.2 (2 − 5.4)2(0.1) = 1.156 4 0.3 4(0.3) = 1.2 (4 − 5.4)2(0.3) = 0.588 6 0.4 6(0.4) = 2.4 (6 − 5.4)2(0.4) = 0.144 8 0.2 8(0.2) = 1.6 (8 − 5.4)2(0.2) = 1.352

Consider a tack like the one pictured below. When dropped on a table, the tack can land either point down or point up. Suppose we assume that P(tack lands point down) = 0.40. Which of the following must be true? (A) If the tack is dropped 50 times and lands point down only 10 times, then it must land point down more than 40% of the time in the next 50 drops. (B) If the tack is dropped on a table 10 times, it will land point down 4 times. (C) If the tack is dropped on a table 1,000,000 times, it will land point down 400,000 times. (D) Over many tack drops, the proportion that land point down will be very close to 0.40. (E) The tack landed point down twice in a simple random sample of 5 people who dropped it on a table.

If you found t(70) = 1.70, how many participants are there? 69 70 71 There is not enough information to determine given this information

Find P(|Z| ≤ 2.5). (round to three decimal places.