4) Variance in drug weights is critical in the pharmaceutical industry. For a specific drug with weights measured in grams if the variance is greater than 0.28 the drug could be ineffective. A sample of 18 pills provided a sample variance of 0.36.
(a) Is there evidence to say that the drug variance is too high to be effective with 95% confidence?

(b) Construct a 90% confidence interval for the population variance.

Researchers were interested in whether there was a linear relationship between a person's armspan (x) and a person's height (y). The data is shown below.

a) Find the least squares line between armspan (x) and height (y) based on the data.

??? =  
??? =  
b =  
a =

?̂ = ___ + ___ x

b) Interpret the meaning of the estimate of the slope ?.

Armspan/height increases/decreases by ______ for every unit increase in armspan/height

Describe two factors that could affect the probability of making a type two error and how they affect it (increasing/decreasing the chance of type two error)

how to recognize each of the following (in a study)
one-sample t  
2 independent sample t
related sample t  
one-sample z-test

A professor at a local community college noted that the grades of his students were normally distributed with a mean of 74 and a standard deviation of 10. The professor has informed us that 6.4 percent of his students received A's while only 2.5 percent of his students failed the course and received F's. What is the minimum score needed to earn an A? Enter your answer rounded to one decimal place.

A researcher tests a new drug on a sample of known schizophrenic patients, hypothesizing it will reduce their symptoms. After the drug trial their symptom scores are assessed (higher scores = more disordered, lower scores = more healthy). This score is converted into a z score of -2.11. The researcher used an alpha of .05.

a. What is the p-value for this study?

b. What do you conclude from this test?

c. What does the p value mean or what does it tell us? Explain the information it conveys about the mean score obtained for the tested sample

show work

Describe the nature of REPO transactions and its targets. Provide the volumes in Q4 2019 for NBP (Narodowy Bank Polski).

please give concrete answer with data.

How do you do this on a ti-84 calculator?

Assume adult females have pulse rates that are normally distributed with a mean of 74.0 beats per minute and a standard deviation of 12.5 beats per minute. If 16 adult females are randomly selected, find the probability that they have pulse rates with a mean between 78 beats per minute and 90 beats per minute.

Suppose a novel respiratory disease has a 2% mortality rate. If 1,000 people catch the disease, how many would you expect to die from it? Give the distribution of the r.v. you’re using to model this situation, including parameter values. How many people would have to catch the disease for the number of expected deaths to rise to 100,000? To rise to 1,000,000?

1. An IQ test is designed so that the mean is 100 and the standard deviation is 24 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics such that it can be said with 90% confidence that the sample mean is within 4 IQ points of the true mean. Assume that o=24 and determine the required sample size. Then determine if the required sample size is a reasonable sample size for a real world calculation.

2. The ages of a group of 135 randomly selected fenal adults have a standard deviation of 18.5 years. Assume that the ages of female statistics students have less variation than ages of females in the general population, so let o=18.5 years for the sample size calculation. How many female statistics student ages must be obtained in order to estimate the mean of all female statistics students? Assume that we want 98% confidence that the sample mean is within one-half year of the population mean. Does it seem reasonable to assume that the ages of female statistics students have less variation than ages of females in the general poulation?

3. The pulse rates of 142 randomly selected males very from a low of 36 bpm to a high of 112 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 98% confidence that the sample mean is within 4 bpm of the population mean.

Q.1 A security system uses a 2-letter password, but no letter can be used more than once. How many possible passwords are there if 15 of the letters of the alphabet can be used by the system? (Use these numbers for this question only!)

For this question indicate only what the value of N is?

Q2.

A security system uses a 5-letter password, but no letter can be used more than once. How many possible passwords are there if 25 of the letters of the alphabet can be used by the system? (Use these numbers for this question only!)

For this question indicate only what the value of r is?

Q3.

A security system uses a four-letter password, but no letter can be used more than once. How many possible passwords are there if 22 of the letters of the alphabet can be used by the system? (Use these numbers for this question only!)

If a gambler rolls two dice and gets a sum of seven, he wins $10, and if he gets a sum of four, he wins $25. The cost to play the game is $5.

A. Give the probability distribution of the winnings for this game.

B. What are the expected winnings for a person who plays this game?

Determine the margin of error for a 99% confidence interval to estimate the population mean when s=45 for the sample sizes of n=15, n=34, n=54. (Find the margin of error for each interval when n=x)

Determine the margin of error for a confidence interval to estimate the population mean with n=24 and s=12.3 for confidence levels 80%, 90%, 99%.

1, 33% of consumers read the ingredients listed on a product's label. For a sample of 265 consumers, what is the probability that between 80 and 103 of them read the ingredients listed on a product's label?

2.

The hotel room rate in New York City is normally distributed with a mean of $294 per night. Assume that the standard deviation is unknown.

If 23% of the New York City hotel room rates are more than $328 per night, what is the variance? (Remember the label.)

3.

The Economic Policy Institute reports that the average entry-level wage for male college graduates is $22.23 per hour and for female college graduates is $18.97 per hour. The standard deviation for male graduates is $3.94 and for female graduates is $3.02. Assume wages are normally distributed.

If 30 female graduates are chosen, find the probability the sample average entry-level wage is at least $19.85

Eighty percent of flights arriving in Atlanta for a large US airline are on time. If the FAA randomly selects 50 of the airline's flights, find the probability that:

a. at least 85% of the sampled flights will be on time.

b. at most 70% of the sampled flights will be on time.

c. between 75% and 85% of the sampled flights will be on time.