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 )

Determine whether the following statement is true or false. To construct a confidence interval about the mean, the population from which the sample is drawn must be approximately normal. This statement is

A survey of 2283 adults in a certain large country aged 18 and older conducted by a reputable polling organization found that 406 have donated blood in the past two years. Complete parts (a) through (c) below. Click here to view the standard normal distribution table (page 1). Click here to view the standard normal distribution table (page 2) \( \begin{array}{l}\text { (a) Obtain a point estimate for the population proportion of adults in the country aged } 18 \text { and older who have donated blood in the past two years. } \\ \text { (Round to three decimal places as needed.) }\end{array} \)

Ork Explain why the \( t \)-distribution has less spread as the number of degrees of freedom increases. Choose the correct answer below. A. The \( t \)-distribution has less spread as the degrees of freedom increase because, as \( n \) increases, 2 of 8 posints information is known about \( \sigma, 9.2 .49 \) by the law of large numbers. B. The \( t \)-distribution has less spread as the degrees of freedom increase because, as \( n \) increases, s becomes closer to \( \sigma \) by the law of large numbers. C. The \( t \)-distribution has less spread as the degrees of freedom increase because, for large values of \( n \), \( n \geq 30 \), the \( t \)-distribution and the normal distribution are the sam D. The \( t \)-distribution has less spread as the degrees of freedom increase because the variability introduced into the \( t \)-statistic becomes greater as \( n \) increases.

The grades on the second statistics test for Mrs. Sweeney's class are in the following list. Find the frequency distribution for the grades. \[ \text { D, F, B, D, A, F, F, B, F, F, B, C, C, C, B, F, C, A, B B, B F } \] Answer

What is a scatter plot?