The mean attention span for adults in a certain village is 15 minutes with a standard deviation of 6.4.  If many samples of size 30 are taken from that population, and a sampling distribution of their means is created,  (SEM) will equal __________

Suppose the prices of a gallon of milk at various stores in one town have a mean of $3.76 with a standard deviation of 0.15 using thechebyshev’s theorem. what is the minimum percentage of stores that sell a gallon of milk for between 3. 46 and $4.06 round your answer to one decimal place .please

In a large section of a statistics​ class, the points for the final exam are normally​ distributed, with a mean of 69 and a standard deviation of 8. Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's. Find the lowest score on the final exam that would qualify a student for an​ A, a​ B, a​ C, and a D. The lowest score that would qualify a student for an A is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a B is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a C is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a D is nothing. ​(Round up to the nearest integer as​ needed.)

The amounts of electricity bills for all households in a particular city have an approximately normal distribution with a mean of $135 and a standard deviation of $25. Let I be the mean amount of electricity bills for a random sample of 24 households selected from this city. Find the mean and standard deviation of

Suppose that the lengths of pregnancies are normally distributed with a mean of 271 days and a standard deviation of 10 days.  find the percentage of pregnancies that are longer than 254 days. For your intermediate computations, use four or more decimal places. Give your final answer to two decimal places (for example 98.23%).

Suppose that the distribution of Writing SAT scores from your state this year is normally distributed with mean 480 and standard deviation 110 for males, and mean 500 and standard deviation 100 for females. How well did Mary's score of 670 rate in terms of the scores of male students? Mary did better than approximately ____% of male students taking the test.

In a large section of a statistics​ class, the points for the final exam are normally​ distributed, with a mean of 74 and a standard deviation of 8. Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's. Find the lowest score on the final exam that would qualify a student for an​ A, a​ B, a​ C, and a D. The lowest score that would qualify a student for an A is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a B is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a C is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a D is nothing. ​(Round up to the nearest integer as​ needed.)

With a mean of 10 and standard deviation of 5. Assume that the population data are normally distributed.  Calculate the z-score for a raw score of 5. What proportion of the distribution is equal to or less than this score?

suppose that a category of world-class runners are known to run a marathon (26 miles) in an average of 143 minutes with a standard deviation of 14 minutes. consider 49 of the races. Let x̅ = the average of the 49 races. I need help finding the median of the average running times. if someone could explain how to solve this problem that would be great

to qualify for membership in a certain high-IQ society a person must score in the upper 2% of the population on an IQ test. the minimum IQ score to be in the upper 2% is a 140.5 if Iq scores are normanlly distributed with a standrd deviation of 10, what is the mean IQ score?