A doctor wants to estimate the mean HDL cholesterol of all 20 - to 29 -year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 3 points with \( 99 \% \) confidence assuming \( \mathrm{s}=12.9 \) based on earlier studies? Suppose the doctor would be content with \( 90 \% \) confidence. How does the decrease in confidence affect the sample size required? Click the icon to view a partial table of critical values. A \( 99 \% \) confidence level requires \( \square \) subjects. (Round up to the nearest subject.) A \( 90 \% \) confidence level requires \( \square \) subjects. (Round up to the nearest subject.) How does the decrease in confidence affect the sample size required? B. Decreasing the confidence level decreases the sample size needed. B. Decreasing the confidence level increases the sample size needed.

A person's blood glucose level and diabetes are dosely related. Let \( x \) be a random variable measured in milligrams of glucose per deciliter ( \( 1 / 10 \) of a liter) of blood. Suppose that after a 12 -hoi fast, the random variable \( x \) will have a distribution that is approximately normal with mean \( \mu=87 \) and standard deviation \( \sigma=23 \). Note: After 50 years of age, both the mean and standard deviation tend to increase. For an adult (under 50 ) after a 12-hour fast, find the following probabilities. (Round your answers to four decimal places.) (a) \( x \) is more than 60 (b) \( x \) is less than 110 (c) \( x \) is between 60 and 110 (d) \( x \) is greater than 125 (borderline diabetes starts at 125 )

How many college students are needed to estimate the mean grade point average of all current college students in the United Sates within 20\% percentage points with a \( 99 \% \) confidence. An earlier study gave an estimate of 0.79 for the population standard deviation. \( \mathrm{n}= \)

The test scores of 40 students are listed below. Find \( \mathrm{P}_{85} \). \( \begin{array}{l}30,35,43,44,47,48,54,55,56,57,59,62,63,65,66,68,69,69,71,72,72,73, \\ 74,76,77,77,78,79,80,81,81,82,83,85,89,92,93,94,97,98\end{array} \)

Что такое диаграмма рассеяния и для чего она используется?

Question 8 The heights of 10 -year-olds, regardless of gender, closely follow a Normal distribution with a mean of 56 inches and a standard deviation of 5 inches. a. What is the probability that a randomly chosen 10 -year-old is shorter than 48 inches? (Round to 4 decimal places.) b. If the tallest \( 10 \% \) of the class is considered "very tall", what is the height cutoff for "very tall"? (Round to 2 decimal places.) [SAB2]