Questions from Engineering Statistics

Q: Given a random sample of size 24 from a normal distribution,

Given a random sample of size 24 from a normal distribution, find k such that (a) P(−2.069 < T < k) = 0.965; (b) P(k < T < 2.807) = 0.095; (c) P(−k < T < k) = 0.90.

Q: Refer to Exercise 9.22 again. Suppose that specifications by

Refer to Exercise 9.22 again. Suppose that specifications by a buyer of the thread are that the tensile strength of the material must be at least 62 kilograms. The manufacturer is satisfied if at most...

Q: A manufacturing firm claims that the batteries used in their electronic games

A manufacturing firm claims that the batteries used in their electronic games will last an average of 30 hours. To maintain this average, 16 batteries are tested each month. If the computed t-value fa...

Q: A normal population with unknown variance has a mean of 20.

A normal population with unknown variance has a mean of 20. Is one likely to obtain a random sample of size 9 from this population with a mean of 24 and a standard deviation of 4.1? If not, what concl...

Q: The numbers of incorrect answers on a true-false competency test

The numbers of incorrect answers on a true-false competency test for a random sample of 15 students were recorded as follows: 2, 1, 3, 0, 1, 3, 6, 0, 3, 3, 5, 2, 1, 4, and 2. Find (a) the mean; (b) th...

Q: A maker of a certain brand of low-fat cereal bars

A maker of a certain brand of low-fat cereal bars claims that the average saturated fat content is 0.5 gram. In a random sample of 8 cereal bars of this brand, the saturated fat content was 0.6, 0.7,...

Q: For an F-distribution, find (a) f0

For an F-distribution, find (a) f0.05 with v1 = 7 and v2 = 15; (b) f0.05 with v1 = 15 and v2 = 7: (c) f0.01 with v1 = 24 and v2 = 19; (d) f0.95 with v1 = 19 and v2 = 24; (e) f0.99 with v1 = 28 and v2...

Q: Pull-strength tests on 10 soldered leads for a semiconductor device

Pull-strength tests on 10 soldered leads for a semiconductor device yield the following results, in pounds of force required to rupture the bond: Another set of 8 leads was tested after encapsulatio...

Q: Consider the following measurements of the heat-producing capacity of the

Consider the following measurements of the heat-producing capacity of the coal produced by two mines (in millions of calories per ton): Mine 1: 8260 8130 8350 8070 8340 Mine 2: 7950 7890 7900 8140 79...

Q: Construct a quantile plot of these data, which represent the lifetimes

Construct a quantile plot of these data, which represent the lifetimes, in hours, of fifty 40-watt, 110- volt internally frosted incandescent lamps taken from forced life tests: