STA2014 Statistics - OL1SUT15 Essays (492 words) -

STA2014: Statistics - OL1SUT15 City College Assignment Week 9 Jaime Mesia STA2014: Statistics - OL1SUT15 City College Assignment Week 9 Jaime Mesia Exercises 8-1, page 410. Questions 1, 3, 4, and 9 . Q1 . - Define null and alternative hypotheses, and give an example of each. The null hypothesis usually symbolized by H0 is statistical hypothesis that states that there is no difference between a parameter and a specific value or that there is no difference between two parameters. The alternative hypothesis, denoted by H1, is a statistical hypothesis that there is some difference between a parameter and a specific value or that there is a difference between two parameters. Example: suppose one is going to check whether a coin is unbiased or not. So if p denotes the probability of getting head then the null and alternative hypotheses are: Q3 . - What is meant by a statistical test? A statistical test is a test that uses the data obtained from the sample to make a decision about whether the null hypothesis should be rejected. Q4 . - Explain the difference between a one-tailed and a two-tailed test two-tailed test. A one tailed test means that the null hypothesis should be rejected when the test value is in critical region on one side of the mean. So a one tailed test can be left tailed or right tailed test depending on the direction of the inequality of the alternative hypothesis. On the other hand in a two-tailed test the null hypothesis should be rejected when the test values is in either of the two critical regions. For a two-tailed test the critical region must be split into two equal parts. Q9.- When should a one-tailed test be used? A two-tailed test? A one-tailed test should be used when the alternative hypothesis is about a specific direction, such as greater than or less than. However, a two-tiled should be used when no direction is specified. 1. Hospitals and Nursing Homes Find the Spearman rank correlation coefficient for the following data, which represent the number of hospitals and nursing homes in each of seven randomly selected states. At the 0.05 level of significance, is there enough evidence to conclude that there is a correlation between the two? Hospitals 107 61 202 133 124 117 108 Nursing Homes 230 134 704 376 431 538 373 2. Calories and Cholesterol in Fast-Food Sandwiches Use the Spearman rank correlation coefficient to see if there is a linear relationship between these two sets of data, representing the number of calories and the amount of cholesterol in randomly selected fast-food sandwiches. Calories 580 580 270 470 420 415 330 430 Cholesterol 205 225 285 270 185 215 185 220