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1. The average Senior High School in Quezon City has 1000 students with a standard deviation of 85 students. If a random sample of 38 schools is selected, what is the probability that the mean number of students enrolled is between 970 to 1020? ment 2. In a study of life expectancy of 500 people in a certain province in Sothern Luzon, the mean age at death was 70 years and the standard deviation is 5 years. If a sample of 50 people from this province is selected, what is the probability that the mean life expectancy will be less than 68 years? 3. The average number of milligrams of cholesterol in a cup of a certain brand of ice cream is 660 mg., and the standard deviation is 35 mg. If a sample of 30 cups of ice cream is selected, what is the probability that the means of the sample will be larger than 670 mg? es! 4. The height of 600 Grade 11 students in a certain Senior High School were measured with a mean of 68 inches and a standard deviation of 7 inches. If 35 students are selected from the population, what is the probability that the height of the chosen group will have a mean less than 67 inches? 5. An electrical company claims that the average life of the bulbs it manufactures is 1200 hours with a standard deviation of 250 hours. If a random sample of 100 bulbs is chosen, what is the probability that the sample mean will be a. greater than 1150 hours? b. less than 1250 hours? c. between 1150 and 1250 hours