# Statistics

### QNT 275 Final Exam Section 5 – Regression Analysis

Which of the following violates the assumptions of regression analysis? The error term does not have the normal distribution. Explanation: There are a number of assumptions that must be made in a regression analysis. One of the keys is that the error term has a normal [...]Read more

### QNT 275 Final Exam Section 6 – Frequency Distributions

Frequency distributions may be used to describe which of the following types of data? Nominal, ordinal, interval, and ratio data Explanation: Frequency distributions simply collect the number of times a value appears in a set. This is used commonly with qualitative data, but [...]Read more

### Cold and Flu Study Statistical Analysis

Which is the Better Medication for both a Sore Throat and a Fever? Medication Study Details Sore throat – Medication A: Success rate – 90%101 out of 112 trials were successful) Sore throat – Medication B: Success rate – 83%(252 out of 305 trials were [...]Read more

### Why a Statistician Wanted to Reinforce Airplane Engines during WWII

Abraham Wald, Airplane Engines, and Statistics The statistician who worked with the U.S. Military in this scenario is Abraham Wald. He is well-known for making the correlation between bullet hole location the unexpected results that they produce for aircraft reinforcement. Wald [...]Read more

### Random Sample Confidence Interval – QNT/561 Week 2 Lab

QNT/561 Week 2 Lab – Random Sample A random sample of 90 observations produced a mean x = 25.7 and a standard deviation s = 2.6. a . Find a 95% confidence interval for μ b. Find a 90% confidence inteml for μ c. Find a 99% confidence interval for μ Solution Use the [...]Read more

### Newspaper Reported that Coffee Shops are Overpriced – QNT/561 Week 2 Lab

QNT/561 Week 2 Lab – Coffee Shops are Overpriced A newspaper reported that 50% of people say that some coffee shops are overpriced. The source of this information was a telephone survey of 40 adults . a. Identify the population of interest in this study b. Identify the [...]Read more

### Reading program to improve students’ Japanese reading comprehension – QNT/561 Week 2 Lab

QNT/561 Week 2 Lab – Japanese Language Program In one university, language professors incorporated a 10-week extensive reading program to improve students’ Japanese reading comprehension. The professors collected 277 books originally written for Japanese children and [...]Read more

### Mailing Service Performance – QNT/561 Week 2 Lab

QNT/561 Week 2 Lab – Mailing Service An accounting firm annually monitors a certain mailing service’s performance. One parameter of interest is the percentage of mail delivered on time. In a sample of 306,000 items mailed between Dec: 10 and Mar 3 – the most [...]Read more

### Hypothesis Test Conducted at α= 0.025 – QNT 561 Lab Week 3

Hypothesis Test Conducted using α= 0.025 If a hypothesis test were conducted using α= 0.025, for which of the following p-values would the null hypothesis be rejected? Solution at 0.024 Reject the null hypothesis since the p-value is less than the value of a. Explanation: When [...]Read more

### A random sample of size n=100 yielded p=0.50 – QNT/351 Week 2 Lab

QNT/561 Week 2 Lab – Random Sample of n=100 and p=0.50 A random sample of size n= 100 yielded p = 0.50 a Is the sample size large enough to use the large sample approximation to construct a confidence interval for p? Explain. b. Construct a 95% confidence interval for p. [...]Read more