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Calculate the standard deviation and CV for the age distribution presented below:
Age: 09.5-12.5 12.5-15.5 15.5-18.5 18.5-21.5 21.5-24.5 24.5-27.5 27.5-30.5
Frequency: 3 14 23 12 8 4 1
Explain your results
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A company sends a random sample of 16 of its sales- people to a course designed to increase their moti- vation and, hence, presumably their effectiveness. In the following year these people generated sales with an average value of $625,000 and a sample stan- dard deviation of $80,000. During the same period, an independently chosen random sample of 10 sales- people who had not attended the course obtained sales with an average value of $608,000 and a sample standard deviation of $73,000. Assume that the two population distributions are normal and have the same variance. Find a 90% confidence interval esti- mate for the difference between the population mean sales for salespeople who attended the motivational course and for those salespeople who did not attend the course.
A proposal for a new 1-cent tax increase to support can- cer research is to appear on the ballot in one county’s next election. The residents in Hangzhou and Chengdu, two cities in China, were questioned as to their level of support. In Hangzhou a recent survey of 450 resi- dents showed that 352 people supported the proposal, 18 were undecided, and the remainder were opposed to the new proposal. In Chengdu, the results of a ran- dom sample of 400 residents found that 326 people supported the tax, 32 were opposed, and the remainder
A newspaper article reported that 350 people in one state were surveyed and 60% were opposed to a recent court decision. The same article reported that a similar survey of 550 people in another state indicated oppo- sition by only 20%. Construct a 95% confidence inter- val of the difference in population proportions based on the data.
You are the operations manager for XYZ Cereal Company and is responsible for monitoring the amount of cereal box filled. You select and weigh a random sample of 50 boxes in order to calculate a sample mean and investigate how close the fill weights are to the company’s specifications of a mean of 368 grams. Suppose the sample of 50 boxes indicates a sample mean of 372.5 grams and the population standard deviation is assumed to be 15 grams. This time you must make a decision and conclude whether(or not) the fill mean weight in the entire process is equal to 368 grams in order to know whether the fill process needs adjustment. How could you rationally make this decision?
A bolt machine produced 250 bolts, of which, 50 are defective. If two bolts are picked at random with replacement, what is the probability that both are defective bolts? *
Express your final answer as a fraction in the lowest term (e.g. 1/4)
Determine whether the test is two-tailed or one-tailed. If it is one-tailed, is it left-tailed or right-tailed? Sketch the graphical representation of the test.
1. A nutritionist claims that her developed bread is fortified with vitamin B.
2. A musician believes that listening to classical music affects mood.
3. A storekeeper thinks that time of day influences sale of ice cream.
4. A mother wants to prove that reading books to children improves their thinking processes.
5. A certain combination of fruits provides the daily requirement for vitamin C.
Interpret its value in the context of throwing a die
A student has 6 different notebooks and decided to give 5 of them to a friend. How many ways does he have to give away these notebooks?
#340153 on Dec 2023