can you solve this
1. State the appropriate null and alternative hypothesis in each of the following cases:
a. The Battalion recently changed the format of their opinion page, you want to see what
the students think of this change. You take a random sample of students and select those
who regularly read the Battalion. They are asked to indicate their opinions on the
changes using a 5-point scale. -2 if the new format is much worse than the old, -1 if the
new format is worse than the old, 0 if the old format is the same as the old, 1 if the new
format is better than the old and 2 if the new format is much better than the old.
b. The average square footage of one bedroom apartments in a new student housing
development is advertised to be 880 square feet. A student group thinks that the
apartments are smaller than advertised. They hire an engineer to measure a sample of
apartments to test their suspicion.
c. The diameter of a spindle in a small motor is supposed to be 5 mm. If the spindle is
either too small or too large, the motor will not work properly. The manufacturer
measures the diameter in a sample of motors to determine whether the mean diameter
has moved away from the target.
d. Census Bureau data show that the mean household income in the area served by a
shopping mall is $42,500 per year. A market research firm questions shoppers at the
mall. The researchers suspect the mean household income of mall shoppers is higher
than that of the general population.
2. A vocabulary test is known to have a mean score of 68 and a standard deviation of
13. A class of 19 students takes the test and has a mean score of 65. (Use the
appropriate test to check if the class score is really different.)
3. In the population, the average IQ is 100. A team of scientists want to test a new
medication to check if it has positive or negative impact on intelligence, or no effect
at all. A sample of 30 participants who have taken the medication has a mean of 140
with standard deviation of 20. Did medication affect intelligence?
4. A sample of size n = 100 produced the sample mean of X¯ = 16. Assuming the
population standard deviation s = 3, compute a 95% confidence interval for the
population mean µ.
5. The operations manager of a large production plant would like to estimate the mean
amount of time a worker takes to assemble a new electronic component. Assume
that the standard deviation of this assembly time is 3.6 minutes.
a. After observing 120 workers assembling similar devices, the manager noticed that their
average time was 16.2 minutes. Construct a 92% confidence interval for the mean
assembly time.
b. How many workers should be involved in this study in order to have the mean assembly
time estimated up to ±15 seconds with 92% confidence?
6. You work for a consumer advocate agency and want to find the mean repair cost of
a certain brand of washing machine. As part of your study, you randomly select 40
repairs, determine their costs, and find the mean to be $100.00 with a standard
deviation of $17.50.
a. Construct a 90% confidence interval for the mean repair cost. (Include all three steps:
check conditions, calculate the CI, and interpret it in context.)
b. Construct a 95% confidence interval. (You don’t need to check the conditions again, but
calculate the CI and interpret it in context).
c. Construct a 99% confidence interval. (Again interpret it in context).
"You need a similar assignment done from scratch? Our qualified writers will help you with a guaranteed AI-free & plagiarism-free A+ quality paper, Confidentiality, Timely delivery & Livechat/phone Support.
Discount Code: CIPD30
Click ORDER NOW..
