Find the probability that a standard normal variable z falls between 0.10 and 0.31. (Provide your answer as a number between 0 and 1, rounded to 4 decimals.)

A normal distribution has a mean of µ = 100 with σ = 20. If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 100 and X = 130?​   a. ​0.9332   b. ​0.0668   c. ​0.8664   d. ​0.4332

Assume that the mean height of men in the United States is 70 inches, with a standard deviation of 3 inches.  A particular man is 80 inches tall.  Find the z-score of his height.  (Round to two decimal places.)

Calcium levels in people are normally distributed with a mean of 9.7 mgdL and a standard deviation of 0.5 mgdL . Individuals with calcium levels in the bottom 10% of the population are considered to have low calcium levels. Find the calcium level that is the borderline between low calcium levels and those not considered low. Carry your intermediate computations to at least four decimal places. Round your answer to one decimal place.

In a recent survey of 300 students at a university, 120 stated that they had at least one cold during the past academic year. Assuming the distribution is approximately normal, find the point estimate and standard error for the proportion of students who had a cold during the past academic year.  Round your answers to three decimal places, as needed.

The average number of kilos of meat a person consumes in a year is 100 kilos. Assume that the standard deviation is 11 kilos and the distribution is approximately normal. If a sample of 40 individuals is selected, find the probability that the mean of the sample will be 105 kilos or greater per year. Express your answer in percent form with 2 decimal places (with the percent symbol - e.g. 10.00%). type your answer... Next

Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml). 95 86 82 The sample mean is x ≈ 93.8. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that o = 12.5. The mean glucose level for horses should be μ = 85 mg/100 ml. + Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use a = 0.05. (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? H₁:μ >85; H₁: μ = 85; right-tailed 107 99 108 82 91 ⒸH₁: μ = 85; H₁: μ 85; two-tailed H₁: μ = 85; H₁: >85; right-tailed H₁: μ = 85; H₁₂ : μ< 85; left-tailed (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. The Student's t, since n is large with unknown…

A manufacturer of light bulbs finds that one light bulb model has a mean life span of 1025 h with a standard deviation of 83 h.Find the z-scores for lightbulbs which last 850 and 900 h. (Round your answers to two decimal places.) 850 h: z = 900 h: z =

solve a and b

A simple random sample of 736 photographers found that 65% plan to purchase new equipment within the next year. Data follows the normal curve. What is the SD of the sample? Round to three decimal places. Typed and correct answer please. I ll rate accordingly.