The time between ambulance arrivals at the Methodist Hospital emergency room follows an exponential distribution with a mean of 10 minutes. (a) What is the likelihood the next ambulance will arrive in 15 minutes or less? (b) What is the likelihood the next ambulance will arrive in more than 25 minutes? (c) What is the likelihood the next ambulance will arrive in more than 15 minutes but less than 25? (d) Find the 80th percentile for the time between ambulance arrivals. (This means only 20% of the runs are longer than this time.)

Do wearable devices that monitor diet and physical activity help people lose weight? Researchers had 237 subjects who were already involved in a program of diet and exercise use wearable technology for 24 months. They measured their weight (in kilograms) before using the technology and 24 months after using the technology. The 237 differences in weight (weight after 24 months minus weight before using the wearable technology) had ?⎯⎯⎯=−3.5�¯and ?=7.8.. Let ?� be the mean weight difference.     What is the test statistic? Give your answer to three decimal places. ?= Identify the correct interpretation of the results based on your analysis.Which is the correct answer ? There is very convincing evidence that there is a decrease in average weight after wearing the device. There is a small amount of evidence that there is a decrease in average weight after wearing the device. There is very convincing evidence that there is an increase in average weight…

You have developed an exam to measure knowledge of biology and administered it to a large number of people. On this exam, u= 85 and o = 10. You standardize the distribution so that the new mean and standard deviation are u = 50 and o = 5 If someone takes the exam and receives a score of 73 (before the score is transformed), what will this score be once it is transformed for the new (standardized) distribution?

Researchers were interested in assessing whether stress levels are different at the beginning of the semester compared to finals week. To test this, stress was measured in 5 students at the start of the semester and then again at the end of the semester during finals week.   Participant Stress 1 Stress 2 Difference Score (Di) (Di - Mdiff)2 1 22 22 0   2 32 34 -2   3 24 25 -1   4 28 30 -2   5 26 29 -3   What is the SS of the mean differences (i.e., Σ(Di - Mdiff)2)? Round to 2 decimal places.

Data can be approximated quite well by a N(3.4, 3.1) model. Economists become alarmed when productivity decreases. According to the normal model what is the probability that the percent change in worker output per hour from the previous quarter is more than 1.6 standard deviations below the mean? What is the probability that the percent change in worker output from the previous quarter is between -1.56 and 4.33?

Times for a surgical procedure are normally distributed. There are two methods. Method A has a mean of 35 minutes and a standard deviation of 3 minutes, while method B has a mean of 39 minutes and a standard deviation of 1.5 minutes. Which procedure is preferred if the procedure must be completed within 34 minutes? Which procedure is preferred if the procedure must be completed within 40.0 minutes? Which procedure is preferred if the procedure must be completed within 43 minutes?

I tried the two last choice both of them are wrong.

If a set of observations is normally distributed, what percent of these differ from the mean by (a) more than 2.50? (b) less than 0.640?

The distribution of number of goals scored per match in the 15 home and 14 away matches so far this season for one team in the English Premier Soccer League is shown below. HOME AWAY 2 4 Goals Scored Per Match Which of the following statements is true? (A) The mean number of goals scored in AWAY matches is less than the mean number of goals scored in HOME matches. (B) The range of goals scored for AWAY matches is greater than the range of goals scored for HOME matches. (C) The shape of the distribution of HOME goals scored is left-skewed. (D) The median number of goals scored for AWAY matches is more than the median number of goals scored for HOME matches. (E) The number of AWAY matches in which the team scored three or more goals is three.

A psychologist is studying the self image of smokers, as measured by the self-image (SI) score from a personality inventory. She would like to examine the mean SI score,  μ , for the population of all smokers. Previously published studies have indicated that the mean SI score for the population of all smokers is  80  and that the standard deviation is  12 , but the psychologist believes that the value for the mean has decreased. She plans to perform a statistical test. She takes a random sample of SI scores for smokers and computes the sample mean to be  74 . Based on this information, answer the questions below. What are the null hypothesis ( H0 ) and the alternative hypothesis ( H1 ) that should be used for the test? H0 :  μ  is ?less thanless than or equal togreater thangreater than or equal tonot equal toequal to ?748012 H1 :  μ  is ?less thanless than or equal togreater thangreater than or equal tonot equal toequal to ?748012In the…