
1.1 Definitions of statistics, probability, and key terms Read Online
1.2 Data, sampling, and variation in data and sampling Read Online
1.3 Frequency, frequency tables, and levels of measurement Read Online
1.4 Experimental design and ethics Read Online
By the end of this chapter, the student should be able to:
You are probably asking yourself the question, "When and where will I use statistics?" If you read any newspaper, watch television, or use the Internet, you will see statistical information. There are statistics about crime, sports, education, politics, and real estate. Typically, when you read a newspaper article or watch a television news program, you are given sample information. With this information, you may make a decision about the correctness of a statement, claim, or "fact." Statistical methods can help you make the "best educated guess."
Since you will undoubtedly be given statistical information at some point in your life, you need to know some techniques for analyzing the information thoughtfully. Think about buying a house or managing a budget. Think about your chosen profession. The fields of economics, business, psychology, education, biology, law, computer science, police science, and early childhood development require at least one course in statistics.
Included in this chapter are the basic ideas and words of probability and statistics. You will soon understand that statistics and probability work together. You will also learn how data are gathered and what "good" data can be distinguished from "bad."
Question: At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. Above what value do 2.5% of the sample means fall?
Choices:
1.057
1.06
Question: The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 16 fish is taken, what would the standard error of the mean weight equal?
Choices:
0.200
0.800
0.050
0.003
Question: Which of the following about the binomial distribution is not a true statement?
Choices:
Each outcome is independent of the other.
The random variable of interest is continuous.
The probability of success must be constant from trial to trial.
Each outcome may be classified as either "event of interest" or "not event of interest."
Question: For some positive value of Z, the probability that a standard normal variable is between 0 and Z is 0.3340. The value of Z is:
Choices:
0.37
0.07
0.97
1.06
Question: If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomly selected college student will find a parking spot in the library parking lot in less than 3 minutes.
Choices:
0.1915
0.3085
0.3551
0.2674
Question: If n = 10 and p = 0.70, then the mean of the binomial distribution is:
Choices:
14.29
0.07
7.00
1.45
Question: Let X represent the amount of time it takes a student to park in the library parking lot at the university. If we know that the distribution of parking times can be modeled using an exponential distribution with a mean of 4 minutes, find the probability that it will take a randomly selected student between 2 and 12 minutes to park in the library lot.
Choices:
0.556744
0.656318
0.049787
0.606531
Question: A campus program evenly enrolls undergraduate and graduate students. If a random sample of 4 students is selected from the program to be interviewed about the introduction of a new fast food outlet on the ground floor of the campus building, what is the probability that all 4 students selected are undergraduate students?
Choices:
0.0256
1.00
0.16
0.0625
Question: A financial analyst is presented with information on the past records of 60 startup companies and told that in fact only 3 of them have managed to become highly successful. He selected 3 companies from this group as the candidates for success. To analyze his ability to spot the companies that will eventually become highly successful, he will use what type of probability distribution?
Choices:
binomial distribution
hypergeometric distribution
Poisson distribution
None of the above.
Question: In its standardized form, the normal distribution
Choices:
has a mean of 1 and a variance of 0.
has an area equal to 0.5.
cannot be used to approximate discrete probability distributions.
has a mean of 0 and a standard deviation of 1.
Question: Which of the following is true about the sampling distribution of the sample mean?
Choices:
The standard deviation of the sampling distribution is always ?.
The mean of the sampling distribution is always ?.
The shape of the sampling distribution is always approximately normal.
All of the above are true.