Mba510 Week 5 Problem Set

So, we should reject the null hypothesis H0. At a 0.05 level of significance level, we conclude that there is a significant difference between the average height for females and the average height for the males.

2) Compute the standard deviation for each of the four samples. Does the assumption of .21 for the population standard deviation appear reasonable?

So, we have a distribution with a mean of 20,000 and a standard deviation of 5,102.

2. In order to determine the average amount spent in November on Amazon.com a random sample of 144 Amazon accounts were selected. The sample mean amount spent in November was $250 with a standard deviation of $25. Assuming that the population standard deviation is unknown, what is a 95% confidence interval for the population mean amount spent on Amazon.com in November?

(b) The value of Z with an area of 5% in the right tail, but not the sample mean.

9. Assume the weight, W, of a randomly selected adult has a normal distribution with a mean

Let’s assume you have taken 1000 samples of size 64 each from a normally distributed population. Calculate the standard deviation of the sample means if the population’s variance is 49.

The mean birth weight of infants born at a certain hospital in the month of April was 128 oz. with a standard deviation of 10.2 oz. Which of the following is a correct interpretation of standard deviation?

Body weight expressed as a percentage of ideal in an SRS of n = 9 girls selected at random are as follows {114, 100, 104, 94, 114, 105, 103, 105, 96}. Calculate a 95% confidence interval for the population mean µ.

Average household size is about 3.4. Based on the graph above, 15 of the 50 sampled have a

Fry Brothers heating and Air Conditioning, Inc. employs Larry Clark and George Murnen to make service calls to repair furnaces and air conditioning units in homes. Tom Fry, the owner, would like to know whether there is a difference in the mean number of service calls they make per day. Assume the population standard deviation for Larry Clark is 1.05 calls per day and 1.23 calls per day for George Murnen. A random sample of 40 days last year showed that Larry Clark made an average of

The 95% confidence interval for population mean is $169,042.05 for the lower 95% confidence internal and $217,338.34 for the upper 95% confidence interval.

The 95% confidence interval for the population mean is 66,438 to 80,241. This means that there is a 95% confidence that this interval has the population mean.

s squared subscript p=(n1-1)s squared2 subscript1+(n2-1)s squared2 subscript2]/n1+n2-2. The numerator of the function, n1+n2-2, is the degrees of freedom.

Before calculating such estimates for any population mean, one should understand what a confidence interval is. Confidence intervals display ranges of values for a specific probability that the true value of the parameter is located in within each range. These estimates are based on two facts: the probability distribution of all large sample means tend to be bell-shaped, and samples from bell-shaped distributions are more likely to be found close to their true means. So, the higher the levels of confidence, the wider these intervals.