Mathematics, 24.08.2020 01:01, fordd4
Traffic police monitor the speed of vehicles as they travel over a new bridge. The average speed for a sample of 41 vehicles was 81.35 km/h, with the sample standard deviation being 4.52km/h. We will assume that the speeds are Normally distributed, and the police are interested in the mean speed.
Part a) Since the variance of the underlying Normal distribution is not known, inference here would involve the t distribution. How many degrees of freedom would the relevant t distribution have?
Part b) Create a 95 % confidence interval for the mean speed of vehicles crossing the bridge. Give the upper and lower bounds to your interval, each to 2 decimal places. ( ,)
Part c) The police hypothesized that the mean speed of vehicles over the bridge would be the speed limit, 80 km/h. Taking a significance level of 5 %, what should infer about this hypothesis?
A. We should reject the hypothesis since 80 km/h is in the interval found in (b).
B. We should reject the hypothesis since 80 km/h is not in the interval found in (b).
C. We should not reject the hypothesis since the sample mean is in the interval found in (b).
D. We should reject the hypothesis since the sample mean was not 80 km/h.
E. We should not reject the hypothesis since 80 km/h is in the interval found in (b).
Part d) Decreasing the significance level of the hypothesis test above would (select all that apply)
A. not change the Type II error probability.
B. decrease the Type I error probability.
C. either increase or decrease the Type I error probability.
D. not change the Type I error probability.
E. increase the Type I error probability.
Answers: 2
Mathematics, 21.06.2019 16:40, chrisraptorofficial
14 pointslet x be the seats in the small van and y the seats in the large van. how many seats does the large van have? a company uses two vans to transport worker from a free parking lot to the workplace between 7: 00 and 9: 00a. m. one van has 9 more seats than the other. the smaller van makes two trips every morning while the larger one makes only one trip. the two vans can transport 69 people, maximum. how many seats does the larger van have?
Answers: 1
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