Business statistics true/false
The number of defective apples in a single box is an example of continuous variable.
False
The number of defective apples in a single box will be measured on an interval scale.
False
An economics professor bases his final grade on homework, two midterm exams, and a final exam. The homework counts as 10%, each midterm counts as 25%...
True
Any set of normally distributed data can be transformed to its standardized form.
True
As a general rule, an observation is considered an extreme value if its Z score is greater than 3.
True
As sample size increases, the effect of an extreme value on the sample means becomes smaller.
True
For a given level of significance, if the sample size is increased, the power of the test will increase
True
If gasoline purchased...(over 15 samples)
True
If the population distribution is skewed, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.
True
If the population distribution is symmetric, the sampling distribution of the mean can be approximated by the normal distribution if the samples contain 15 observations
True
In a Poisson distribution, the mean and variance are equal.
True
In a boxplot, the box portion represents the data between the first and third quartile values.
True
In left-skewed distributions, the distance from the smallest observation to Q1 exceeds the distance from Q3 to the largest observation.
True
In right-skewed distributions, the distance from Q3 to the largest observation exceeds the distance from the smallest observation to Q1.
True
A worker earns 15 an hour..
False
A normal probability plot may be used to assess the assumption of normality for a particular batch of data.
True
A sampling distribution is a distribution for a statistic.
True
The interquartile range is a measure of variation or dispersion in a set of data
True
The amount of calories contained in a pack of 12 ounce cheese is an example of a discrete variable
false
An Ogive is a cumulative percentage polygon
True
A sampling distribution is defined as the probability distribution of possible sample sizes that can be observed from a given population
False
As sample size increases, the standard error of the mean increases.
False
For a given level of significance, if the sample size is increased, the probability of committing a type 1 error will increase.
False
If the gasoline purchased... (if under 15 samples)
False
In a Poisson distribution, the mean and standard deviation are equal.
False
When using a Poisson distribution to approximate a bionomial distribution, the standard deviation of the Poisson distribution is np where n is the sample size and p is the probability of an event of interest.
False
The probability that a standard normal random variable Z, falls between -1.50 and .81 is .7242
True
The probability that a standard normal random variable, Z, is between 1.50 and 2.10 is the same as the probability Z is between -2.10 and -1.50
True
The standard error of the mean is also known as the standard deviation of the sampling distribution
True
Then central limit theorem ensures that the sampling distribution of the sample mean approaches normal as the sample size increases.
True
Theoretically, the mean, median, and the mode are all equal for a normal distribution.
True
When using a Poisson distribution to approximate a bionomial distribution, the mean of the Poisson distribution is np where n is the sample size and p is the probability of an event of interest.
True
You can use the Poisson distribution to approximate the bionomial distribution when the sample size is large and the probability of an event of interest is very small
True
If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.
true
The geometric mean is useful in measuring the rate of change of a variable over time
true
A population of 200 elements has an arithmetic mean of 10, From this information, it can be shown that the population standard deviation is 15.
False
A statistic is usually unobservable while a parameter is usually observable.
False
As a general rule, an observation is considered an extreme value if its Z score is greater than -3.
False
As a general rule, an observation is considered an extreme value if its Z score is less than 3.
False
Faculty rank (professor to lecturer) is an example of discrete numerical data.
False
In a set of numerical data, the value for Q2 is always halfway between Q1 and Q3.
False
In forming a 90% confidence interval for a population mean from a sample size of 22, the number of degrees of freedom from a t-distribution equals 22.
False
Marital status is an example of a numerical variable.
False
Marital status is an example of an ordinal scaled variable.
False
Student grades (A to F) are an example of continuous numerical data.
False
The Poisson distribution can be used to model a continuous random variable
False
The amount of alcohol consumed by a person per week will be measured on an interval scale
False
The amount of coffee consumed by an individual in a day is an example of a discrete numerical variable.
False
The answer to the question "what is your favorite color"? is an example of an ordinal scaled variable.
False
The answer to the question "what is your sleeping bag temperature rating"? is an example of a ratio scaled variable.
False
The coefficient of variation is a measure of central tendency in the data.
False
The covariance between two investments is equal to the sum of the variances of the investments
False
The date when a production line in a factory is out-of-control will be measured with a ratio scale.
False
The diameters of 10 randomly selected bolts have a binomial distribution
False
The expected return of the sum of two investments will be equal to the sum of the expected returns of the two investments plus twice the covariance between the investments
False
The geometric mean is a measure of variation or dispersion in a set of data
False
The grade level (k-12) of a student is an example of a nominal scaled variable.
False
The grade level of a student (k-12) is an example of a numerical variable.
False
The interquartile range is a measure of central tendency in a set of data
False
The larger the Z score, the father is the distance from the observation to the median.
False
The largest Poisson random variable X can have is n
False
The level of satisfaction (very unsatisfied, fairly unsatisfied, fairly satisfied, very unsatisfied) in a class is an example of nominal scaled variable
False
The level of satisfaction (very unsatisfied, fairly unsatisfied, fairly satisfied, very unsatisfied) in a class is an example of numerical variable.
False
The line drawn within the box of the boxplot always represents the arithmetic mean.
False
The median of the values 3.4,4.7,1.9,7.6, and 6.5 is 1.9
False
The median of the values 3.4,4.7,1.9,7.6, and 6.5 is 4.05
False
The number of customers arriving at a department store in 5-minute period has a binomial distribution
False
The number of males selected in a sample of 5 students taken without replacement from a class of 9 females and 18 males has a binomial distribution.
False
The type of TV one owns is an example of a numerical variable.
False
The type of TV one owns is an example of an ordinal scaled variable.
False
The z score of an observation can never be negative.
False
Using the number of registered voters who turned out to vote for the primary in Iowa to predict the number of registered voters who will turn out to vote in Vermont's primary is an example of descriptive statistics.
False
When we test for difference between the means of 2 independent population, we can only use a two-tailed test.
False
Another name for the mean of a probability distribution is its expected value
true
The 5-number summary consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation.
True
The Z scores can be used to identify outliers.
True
The amount of alcohol consumed by a person per week is an example of continuous variable.
True
The amount of calories contained in a pack of 12 ounce cheese will be measured on a ratio scale.
True
The amount of time a student spent studying for an exam is an example of a continuous variable.
True
The amount of time a student spent studying for an exam will be measured on a ratio scale.
True
The answer to the question "How many hours on average do you spend watching TV every week?" is an example of a ratio scaled variable.
True
The answer to the question "how do you rate the quality of your business statistics course" is an example of an ordinal scaled variable.
True
The coefficient of variation is a measure of relative variation
True
The coefficient of variation is expressed as a percentage
True
The coefficient of variation measures variability in a data set relative to the size of the arithmetic mean.
True
The level of satisfaction (very unsatisfied, fairly unsatisfied, fairly satisfied, very unsatisfied) in a class is an example of categorical variable.
True
The level of satisfaction (very unsatisfied, fairly unsatisfied, fairly satisfied, very unsatisfied) in a class is an example of ordinal scaled variables.
True
The line drawn within the box of the boxplot always represents the median
True
The median of a data set with 20 items would be the average of the 10th and the 11th items in the ordered array.
True
The normal probability plot may be used to assess the assumption of normality of for a particular data set.
True
The number of customers arriving at a department store in a 5-minute period has a Poisson distribution
True
The number of males selected in a sample of 5 students taken without replacement from a class of 9 females and 18 males has a hypergeometric distribution
True
The possible responses to the question "How long have you been living at your current residence?" are values from a continuous variable.
True
The possible responses to the question "how many times in the past three months have you visited a city park? are values from a discrete variable.
True
The variance of the sum of two investments will be equal to the sum of the variances of the two investments plus twice the covariance between the investments
True
Whether the university is private or public is an example of a nominal scaled variable.
True
Whether the university is private or public is an example of categorical variable.
True
A continuous variable may take on any value within its relevant range even though the measurement device may not be precise enough to record it.
True.
A boxplot is a graphical representation of a 5-number summary
True
A population is the totality of items or things under consideration
True
A professor computed the sample average exam score of 20 students and used it to estimate the average exam score of the 1500 students taking the exam was an example of inferential statistics.
True
A sample is the portion of the universe that is selected for analysis.
True
A statistic is usually used to provide an estimate for a usually unobserved parameter.
True
As a general rule, an observation is considered an extreme value if its Z score is less than -3.
True
Compiling the number of registered voters who turned out to vote for the primary in Iowa is an example of descriptive statistics.
True
Data that exhibit an autocorrelation effect violate the regression assumption of independence
True
If a set of data is perfectly symmetrical, the arithmetic mean must be identical to the median
True
If p remains constant in a binomial distribution, an increase in n will increase the variance.
True
If the covariance between two investments is zero, the variance of the sum of the two investments will be equal to the sum of the variances of the investments.
True
If the data set is approximately bell-shaped, the empirical rule will more accurately reflect the greater concentration of data close to the mean as compared to the chebyshev rule
True
If the distribution of a data set were perfectly symmetrical, the distance from Q1 to the median would always equal the distance from Q3 to the median in a box plot.
True
If the population distribution is unknown, in most cases the sampling distribution of sample mean can be approximated by the normal distribution if the sample contains at least 3 observations
True
In a sample size of 40, the sample mean is 15. In this case, the sum of all observations in the sample is X1=600
True
In a set of numerical data, the value for Q3 can never be smaller than the value for Q1.
True
In a set of numerical data, the value of Q3 can never be smaller than the value of Q1
True
In exploratory data analysis, a boxplot can be used to illustrate the median, quartiles, and extreme values.
True
Managers need understanding of statistics to be able to present and describe information accurately, draw conclusions about large population based on small samples, improve processes, and make reliable forecasts.
True
Problems may arise when statistically unsophisticated users who do not understand the assumption behind the statistical procedures or their limitation are misled by results obtained by computer software.
True
Regression analysis is used for prediction, while correlation analysis is used to measure the strengths of the association between two numerical variables
True
Suppose that a judges decisions follow a bionomial distribution and that his verdict is correct 90% of the time. In his next 10 decisions, the probability that he makes fewer than 2 incorrect verdicts is 0.736
True
Suppose that the number of airplanes arriving..
True
Suppose, in a testing hypothesis for the population proportion, the p-value is computed to be 0.043. The null hypothesis should be rejected if the chosen level of significance is .05
True
