# 5 Stat Question

1. A laboratory in Colorado is interested in finding the mean chloride level for a healthy resident in the state. A random sample of 90 healthy residents has a mean chloride level of 100 mEq/L. If it is known that the chloride levels in healthy individuals residing in Colorado have a standard deviation of 36 mEq/L, find a 95% confidence interval for the true mean chloride level of all healthy Colorado residents. Then complete the table below.

Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.

2. Use the calculator provided to solve the following problems:

Consider a t distribution with 6 degrees of freedom. Compute P(-1.68 < t < 1.68). Round your answer to at least three decimal places. Consider a t distribution with 11 degrees of freedom. Find the value of c such that P(t = c) = 0.05 . Round your answer to at least three decimal places. 3. The records of a casualty insurance company show that, in the past, its clients have had a mean of 1.9 auto accidents per day with a variance of 0.0025 . The actuaries of the company claim that the variance of the number of accidents per day is no longer equal to 0.0025 . Suppose that we want to carry out a hypothesis test to see if there is support for the actuaries' claim. State the null hypothesis and the alternative hypothesis that we would use for this test. 4. The mean SAT score in mathematics, u, is 533. The standard deviation of these scores is 48. A special preparation course claims that it’s graduates will score higher, on average, than the mean score 533. A random sample of 31 students completed the course, and their mean SAT score was 537. At the 0.01 level of significance, can we conclude that the preparation course does what it claims? Assume that the standard deviation of the course is also 48. Perform a one tailed t test, and include the degree of freedom. Then fill out the table below. 5. After the premiere of the new comedy Bumblebee, moviegoers were asked in a quick poll whether they liked the movide. Out of 50 adults, 37 said they liked the movie, whereas out of 100 teenagers, 60 said they liked the movie. Fill in the blanks of the statement below to make the statement the most reasonable possible.

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