The average number of days construction workers miss per year is 8. The standard deviation is...
You are interested in finding a 90% confidence interval for the average number of days of class that college students miss each year. The data below show the number of missed days for 12 randomly selected college students. Round answers to 3 decimal places where possible. 12 3 5 0 12 5 0 12 10 11 3 4 a. To compute the confidence interval use a ? z t distribution. b. With 90% confidence the population mean number of days of...
A researcher is interested in finding a 95% confidence interval for the mean number of times per day that college students text. The study included 141 students who averaged 25.7 texts per day. The standard deviation was 21.2 texts. Round answers to 3 decimal places where possible. a. To compute the confidence interval use a tv distribution. 0 and b. With 95% confidence the population mean number of texts per day is between texts. c. If many groups of 141...
A random sample of 57 children with working mothers showed that they were absent from school an average of 5.3 days per term with a standard deviation of 1.8 days. If days absent follows a normal distribution, determine the critical value for the test statistic (z or t) needed to build a 98% confidence interval for the average number of days absent per term for all children. State the positive value only exactly as found in the table (3 decimal...
A researcher wishes to see if the average number of sick days a worker takes per year is greater than 2.8. A random sample of 30 workers at a large department store had a mean of 3.1. The standard deviation of the population is 0.8. Is there enough evidence to support the researchers claim at α = 0.01?
The number of sick days taken (per month) by 200 factory workers is summarized below. Number of Days Frequency 0 − 5 120 6 − 10 65 11 − 15 14 16 − 20 1 Refer to Exhibit 2-3. The cumulative relative frequency for the class of 11 − 15 Question 2 options: is 199 is 0.07 is 1 is 0.995
1. The mayor is interested in finding a 90% confidence interval for the mean number of pounds of trash per person per week that is generated in the city. The study included 209 residents whose mean number of pounds of trash generated per person per week was 34.5 pounds and the standard deviation was 7.5 pounds. Round answers to 3 decimal places where possible a.With 90% confidence the population mean number of pounds per person per week is between ___...
Question 17 The mean of a distribution is 20 and the standard deviation is 2. At least what percentage of the values will fall between 10 and 30? Do not round the percentage. Blank 1 % Question 18 The exam scores of 20 students were recorded as follows: 73, 87, 62, 98, 43, 90, 88, 97, 100, 87, 95, 100, 56, 78, 100, 88, 70, 78, 63, 78 Find the MODE. If there is no mode, type No Mode. If...
1. A random sample of 37 employees in Sweden worked an average number of 231 days per year. The sample standard deviation is 26 days. a) Develop a 95% confidence interval for the average number of work-days per year for all Swedish employees. (6 marks) b) Verbally interpret the meaning of the confidence interval that you found for part a) c) If the desired margin of error for the above confidence interval is 4 days, what size sample is necessary?...
Cars arrive at a toll booth at average rate of 60 per hour. The standard deviation of the time between arrivals is 0.8 minutes. What is the coefficient of variation of the interarrival times of cars?
the mean number of sick days an employee takes per year is believed to be about 10. Members of a personnel department do not believe this figure. They randomly survey B employees. The number of sick days that the mean number is about 107 Conduct a hypothesis test at the 5% level. they took for the past year are as follows: 12; 6; 14 5 11; 6;10. Lt X the number of sick days they took for the past year....