normal distribution

The average number of hours a vehicle is in the parking lot of the company is 8. Assume the variable is normally distributed and the standard deviation is 2 hours. If 10 vehicles are selected at random, then find the probability that the mean number of hours they are kept in the..

The mean weight of girls in grade 12 of school X is 125 pounds, and the standard deviation is 20 pounds. If a sample of 25 girls is selected, then what is the probability that the mean of the sample will be greater than 128 pounds? Assume the variable is normally distributed. =>..

The average age of the employees in an organization is 34 years. Assume the variable is normally distributed and the standard deviation is 4. If 25 employees are selected at random, then find the probability that the sample mean age of the employees is less than 35 years. => 89...

A central office operator has observed that the long distance telephone calls are normally distributed with a mean of 6 minutes and a standard deviation of 2 minutes. If random samples of 32 calls were selected, what is the probability that the length of the sample mean time exc..

Which of the following are the assumptions for two-way ANOVA? I. All samples are drawn from normally distributed populations. II. All populations have a common variance. III. The groups must be equal in sample size. IV. Within each group, the observations were sampled randomly a..

If the blood pressure of healthy men is normally distributed with a mean of 120 mm Hg and a standard deviation of 8, and men with blood pressure levels over 140 mm Hg are diagnosed as not healthy, then what is the probability of a type I error? => 0.0062 or 2.5 or 0.4938 or 0.50..

The university authorities wanted to estimate the average age of the students in their university by taking a random sample of 25 students. The standard deviation was found to be 3 years. Find the 95% confidence interval for the variance (σ 2 ) and standard deviation (σ). Assume that th..

An automobile parts supplier wants to know how long car owners plan to keep their cars with them. A random sample of 20 car owners results in a standard deviation of 3.7 years. Find a 95% confidence interval for the variance and standard deviation. Assume that the variable is normally ..

Say whether the normal distribution can be used as an approximation to the binomial distribution shown here. n = 20 and p = 0.8 => false or true or cannot be determined...

Jason takes 30 minutes for the newspaper distribution in Taloga. Andrew, who normally takes 60 minutes, assists him. How long would it take for both of them, working together, to distribute the newspapers in Taloga? => 20 minutes or 30 minutes 20 seconds or 30 minutes ..