A random sample of 21 waiting times (in minutes) before patients saw a medical professional in a hospital's minor emergency department had a variance of 0.36 minute. After a new admissions procedure was implemented, a random sample of 27 waiting times had a variance of 0.16 minute. At a = 0.01, can you support the hospital's claim that the standard deviation of the waiting times has decreased? Complete parts (a) through (e) below. (a) Identify the claim and state Ho and Ha. Let o represent the initial variance and os represent the variance for the new process. Choose the correct answer below. O A. Ho: of sož. Haio>o? O B. Ho: o? = 03. Hạ:of to? OC. Ho: o? Fo O B. FFo O D. -Fo

A math teacher claims that she has developed a review course that increases the scores of students on the math portion of a college entrance exam. Based on data from the administrator of the exam, scores are normally distributed with H = 525. The teacher obtains a random sample of 2200 students, puts them through the review class, and finds that the mean math score of the 2200 students is 530 with a standard deviation of 119. Complete parts (a) through (d) below. C. Yes, because every increase in score is practically significant. D. No, because the score became only 0.95% greater. (d) Test the hypothesis at the a = 0.10 level of significance with n= 400 students. Assume that the sample mean is still 530 and the sample standard deviation is still 119. Is a sample mean of 530 significantly more than 525? Conduct a hypothesis test using the P-value approach. Find the test statistic. to =0 (Round to two decimal places as needed.) %3D Find the P-value. The P-value is (Round to three decimal…

The mean score on a driving exam for a group of driver’s education students is 76 points, with a standard deviation of 6 points. Apply chebychev’s theorem to the data using K=2. Interpret, At least ___% of the exam score falls between ___and ____

A math teacher claims that she has developed a review course that increases the scores of students on the math portion of a college entrance exam. Based on data from the administrator of the​ exam, scores are normally distributed with μ=515. The teacher obtains a random sample of 2200 students, puts them through the review​ class, and finds that the mean math score of the 2200 students is 521 with a standard deviation of 114. Complete parts​ (a) through​ (d) below. ​(b) Test the hypothesis at the α=0.10 level of significance. Is a mean math score of 521 statistically significantly higher than 515​? Conduct a hypothesis test using the​ P-value approach. Find the test statistic.   t0=

A researcher wishes to estimate the average blood alcohol concentration (BAC) for drivers involved in fatal accidents who are found to have positive BAC values. He randomly selects records from 75 such drivers in 2009 and determines the sample mean BAC to be 0.17 g/dL with a standard deviation of 0.080 g/dL. Complete parts (a) through (d) below. (a) A histogram of blood alcohol concentrations in fatal accidents shows that BACs are highly skewed right. Explain why a large sample size is needed to construct a confidence interval for the mean BAC of fatal crashes with a positive BAC. O A. Since the distribution of blood alcohol concentrations is not normally distributed (highly skewed right), the sample must be large to ensure that the sample size is greater than 5% of the population. O B. Since the distribution of blood alcohol concentrations is normally distributed, the sample must be large to ensure that the sample size is greater than 5% of the population. O C. Since the distribution…

From generation to generation, the average age when smokers first start to smoke varies. However, the standard deviation of that age remains constant at around 2.1 years. A survey of 37 smokers of this generation was done to see if the average starting age is at least 19. The sample average was 18.1 with a sample standard deviation of 1.3. Do the data support the claim at the 5% level? Note: If you are using a Student's t-distribution for the problem, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.) + Part (a) + Part (b) + Part (c) A Part (d) State the distribution to use for the test. (Round your standard deviation to four decimal places.) X - N 19 2.1/37 E Part (e) O Part (f) O Part (g) O Part (h) Indicate the correct decision ("reject" or "do not reject" the null hypothesis), the reason for it, and write an appropriate conclusion. (1) Alpha: a =

The number of peanuts in a 16 ounce can of nut munchies is normally distributed with a mean of 93.6 and a standard deviation of 4.2 peanuts the number of peanuts in a 20 ounce can of gone nuts is normally distributed with a mean of 111.8 and a standard deviation of 3.4 peanuts. (a) Carmen purchased a 16 ounce can of nut munchies and counted 100 peanuts what is the Z score for this can of peanuts? (b) Angelo purchased a 20 ounce can of gone nuts and counted 116 peanuts what is the Z score for this can of peanuts? (c) Carmen declares that purchase purchasing her can of nut munchies with 100 peanuts is less likely than Angelo purchasing a can of gone nuts with 116 peanuts is Carmen statement correct? Use the definition of a Z score to support or refute Carmen's claim.