Scores of the first test in Econ 261 follow a normal distribution with mean 70 and standard deviation 5. Compute the following probabilities. P(64 sX s70) is: .9482 .6343 .3849 .9987

X is a normally distributed random variable with a mean of 5.00 and a standard deviation of 11.39.  If the right area is 0.4716 then what is the value of X?

Suppose that the lifetimes of tires of a certain brand are normally distributed with a mean of 74,500 miles and a standard deviation of o miles. These tires come with a 55,000-mile warranty. The manufacturer of the tires can adjust o during the production process, but the adjustment of o is quite costly. The manufacturer wants to set ở once and for all so that only 1% of the tires will fail before warranty expires. Find the standard deviation to be set. Carry your intermediate computations to at least four decimal places. Round your answer to at least one decimal place. | miles Check esc -> @ 23 24 4. 5 6 1 2 y e tab w/

Suppose that scores on a particular test are normally distributed with a mean of 120 and a standard deviation of 16. What is the minimum score needed to be in the top 15% of the scores on the test? Carry your intermediate computations to at least four decimal places, and round your answer to one decimal place.

From a sample with n=36​, the mean duration of a​ geyser's eruptions is 3.36 minutes and the standard deviation is 0.66 minutes. Using​ Chebychev's Theorem, determine at least how many of the eruptions lasted between 1.38 and 5.34 minutes.   At least (   ?  ) of the eruptions lasted between 1.38 and 5.34 minutes.

Assume the random variable X is normally distributed with a mean of 130 and standard deviation of 21.5. State answers to THREE decimals.   P (140 < x < 165) = P( x > 105) =

Assume all populations are normally distributed. A travel analyst claims that the mean price of a round trip flight from New York City to Los Angeles is less than $507. In a random sample of 55 round trip flights from NYC to LA, the mean price is $502. Assume the population standard deviation is $111. At α = 0.05, is there enough evidence to support the travel analyst’s claim?

Assume that females have pulse rates that are normally distributed with a mean of μ=74.0 beats per minute and a standard deviation of σ=12.5 beats per minute. If 4 adult females are randomly​ selected, find the probability that they have pulse rates with a mean less than 77 beats per minute.   The probability is____