Activity 1

B. State the null hypothesis and the alternative hypothesis in (a) words and in (b) symbols for each of the following. 1 A librarian of a school claims that their grade 8 students read an average of 10 books a month with a standard deviation I of two books. A random sample of grade 8 students read an average of 12 books a month and a standard deviation of 1 | i book. 2. According to a factory employer, the mean working time of workers in the factory is 6 hours with a standard deviation ! i of 0.5 hours. A researcher interview 50% of the employees and found out that their working time is 8 hours with a ! I standard deviation of 1 hour. Is it safe to say that the factory workers work longer than 6 hours? 3. A random sample of 200 students got a mean score of 62 with a standard deviation score of 5 in a knowledge test in math. In the standardization of the test, the u = 50 and o = 10. Did the 200 students perform better? ic. Write N if the statement below is NON-DIRECTIONAL, write D if it is DIRECTIONAL 1 A researcher claims that method of teaching affects learning. 12. A food additive enhances food flavour. 3. A study habit improves memory. | 4. Health is related to lifestyle. 5. Peoples' culture affects tourism D. Read and understand the following situations. Using the steps shown in the examples, solve the following. I In a plant nursery, the owner thinks that the lengths of seedlings in a box sprayed with some kind of fertilizer has an average height of 26 cm after three days and the standard deviation of 10 cm. One researcher randomly selected 80 such ; seedlings and calculated the mean height to be 20 cm and the standard deviation was 10 cm. Is the assumption of the | owner correct? Use a = 0.05. | 2. Suppose that an automobile manufacturer advertises that its new hybrid car has a mean gas mileage of 50 miles per | gallon. You take a simple random sample of n = 30 hybrid vehicles and test their gas mileage. You find that in this ! sample, the average is x = 47 miles per gallon with a standard deviation of s = 5.5 miles per gallon. Does this indicate ! that the average gas mileage is less than what is advertised? Use a = 0.05 3. A manufacturer of sprinkler systems designed for fire protection claims that the average activating temperature is at most 135 F. To test this claim, you randomly select a sample of 32 systems and find the mean activation temperature to | be 138.F with a standard deviation of 3.3 F at a = 0.10, do you have enough evidence to reject the manufacturer's claim? Or the temperature can go higher that what the manufacturer says? 4. The Internal Revenue Service claims that the mean wait time for callers during a recent tax filing season was at most ? minutes. A random sample of 11 callers has a mean wait time of 8.7 minutes and a standard deviation of 2.7 minutes, Is I there enough evidence to reject the claim at a significance level of 0.10?B). | A. For each case, determine the two variables and tell whether the relationship is positive (write A) or negative (write | | 1. The more time is spent in studying his lessons; the higher is the average grade of Nelson 1 2. If the population of fox in the forest increases, the number of deer decreases. 1 3. The more students enrol in a school, the more teachers are needed. 4. As a person ages, his memory decreases. 5. The more workers are hired to paint the whole school, the sooner the job is done. B. Identify the dependent and independent variables. Dependent Independent 1. The type of light used and the rate of tomato growth 2. Amount of phone use before bed and the number of hours of sleep 3. Pressure and depth of water 4. Side and area of a square 5. Time spent studying and your test score I C. Read and understand the situation below. Answer what Is asked. Show complete solution. | 1. The data below shows the age and number of hours of exercise done in a day. Age of person (in years) 18 20 16 24 32 45 52 No. of hours spent in exercise/day 6 4 4 3 2 1 s there a relationship between the age and number of hours of exercise? D. Read and understand the situation below. Answer what is asked. Show complete solution. 1. Survey tests on leadership skills and on self concept were administered to student leaders. Both tests use a 10-point Likert scale with 10 indicating the highest scores for each test. Scores for the student-leaders on the tests follow. Student Code A B C D E F G H I Self-Concept 9.5 9.2 6.3 4.1 15.4 8.3 7.8 6.8 5.6 7.1 Leadership Skill 9.2 8.8 7.3 3.4 6.0 7.8 8.8 7.0 6.5 8.3 a. Compute the coefficient of correlation I. b. Interpret the results in terms of strength and direction of correlation. c. Find the regression line that will predict the leadership skill if the self-concept score is known d. Predict the leadership skill of a student-leader whose self-concept skill is 1.5