1.328 b. 2.539 c. 1.325 d. 2.528 ANSWER: a -go to the t-dtistrubution and use α=0.20 or confidence of 80% and use dof=19 3. Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (upper tail), a sample size of 18 at a .05 level of significance t = a. 2.12 b.
If you choose 40 random employees from the corporation, the standard error would equal 6/Square root of 40 = .95 days. The 12 days in this department corresponds to (12-8.2)/.95 = 4 standard errors above the corporation average of 8.2. This is much higher than two or three standard errors, and it appears to be beyond chance variation. Chapter 9 Exercise 3 The p- value tells you how likely it would be to get results at least as extreme as this if there was no difference in the taste and only chance variation was operating. In this problem, p-value of 0.02 means that, if there is no difference in taste, then there is only 2% chance that 70% or more people would declare one drink better than the
Math 533 Course Project: AJ DAVIS DEPARTMENT STORES Project Part B: Hypothesis Testing and Confidence Intervals Summary Report In order to calculate the probability of each situation hypothesis tests were administered on each scenario. In summary, hypothesis testing is used to check whether there is or is not likely to be a difference between one or more data sets. In statistics there is no such thing as 100% sure so uncertainty must be allowed. Instead the best thing we can do in statistics is to show things are false to make the best inferences. The following information below describes what was concluded from the hypothesis tests below.
The alternative hypothesis H1 is that the mean annual income μ is less than $50,000. H1:μ < $50,000 Significance level chosen is 5% or α = 0.05 Here, the population standard deviation is unknown. Hence, we use a t statistic Therefore the test statistic used is t = X-μS/n follows a t distribution with n-1 degrees of freedom From the t table corresponding to 0.05 probability, the critical value tα =1.6766. Hence the critical region is t < -1.6766. Alternatively, we reject the null hypothesis, if the p value is less than the significance level Substituting the value we get t = 43.74-5014.6396/50 = -3.02 The p value corresponding to t = -3.02 and 49 d.f.
Answer: True Difficulty: Medium (REF) 9. The reason sample variance has a divisor of n-1 rather than n is that it makes the variance an unbiased estimate of the population variance. Answer: True Difficulty: Hard 10. The standard deviation of all possible sample proportions increases as the sample size increases. Answer: False
p.286. no 10.- Two hundred draws will be made at random with replacement from the box -3, -2, -1, 0, 1, 2, 3 (a) If the sum of the 200 numbers drawn is 30, what is their average? (b) If the sum of the 200 numbers drawn is –20, what is their average? (c) In general, how can you figure the average of the 200 draws, if you are told their sum? (d) There are two alternatives: (i) Winning $1 if the sum of the 200 numbers drawn is between –5 and +5 6 Winning $1 if the average of the 200 numbers drawn is between –0.025 and +0.025.
STAT 1008 Assignment One Question 1 (a) The main purpose of statistics is that when the size of the population is not manageable, a sample of manageable size should be drawn from the population. While we are ultimately interested in some numerical aspect of the population, we also hope that some numerical aspect of the sample would reflect the numerical aspect of the population that we are interested in. Thus, there is no need to use census. (b) Stratified sampling is recommended. Stratified sampling is commonly used in the scenario described in the assignment spec.
The alternative hypothesis is a statement that is accepted only if the data proves evidence is true. This typically represents the values of a population parameter in which the researcher wants to gather evidence to support the hypothesis (McClave, Benson, & Sincich, 2011). The next steps are to select the appropriate test statistic and level of significance. The z-test is typically used when testing a hypothesis of a proportion and a t-test is used when testing a hypothesis of a mean. The test statistic is used to determine whether the researcher should use the null or alternative hypothesis.
The smallest relative difference that is not statistically significant is stress management at -0.63. The reason that this ratio is not statistically significant is because the value used to determine significance was lower than 0.05. The smaller t ratio has an increased p value and the odds of being able to reject the null hypothesis are diminished. This result means
TOP: Find probabilities for binomial experiments. KEY: Probability | Binomial Experiments 30. ANS: A Identify the parameters of binomial distribution and calculate the probability of the given event using binomial expansion. |Feedback| A|Correct!| B|Did you use the formula to calculate the probability of a binomial experiment correctly?| C|What is the total number of hurdles to be crossed?| D|This is the probability of knocking down two hurdles.| PTS: 1 DIF: Advanced REF: Page 679 OBJ: 12-8.2 Find probabilities for binomial experiments. TOP: Find probabilities for binomial experiments.