Stats.
What symbol is used for sample mean?
- x
Determine whether the value given below is from a discrete or continuous data set. In an election poll, Josh received 17,328,231 votes.
A discrete data set because there are a finite number of possible values.
How is a sample related to a population?
A sample is a subset of a population.
Why shouldn't classes overlap when summarizing continuous data in a frequency or relative frequency distribution?
Classes shouldn't overlap so there is no confusion as to which class an observation belongs.
Which branch of statistics deals with the organization and summarization of collected information?
Descriptive statistics
Determine whether the statement is true or false. A statistic is a measure that describes a population characteristic.
False. A statistic is a measure that describes a sample characteristic.
What does it mean when sampling is done without replacement?
Once an individual is selected, the individual cannot be selected again
What is the difference between relative frequency and cumulative frequency?
Relative frequency of a class is the percentage of the data that falls in that class, while cumulative frequency of a class is the sum of the frequencies of that class and all previous classes
To estimate the percentage of defects in a recent manufacturing batch, a quality control manager at Toshiba selects every 14th laptop that comes off the assembly line starting with the tenth until she obtains a sample of 40 laptops. What type of sampling is used?
SYSTEMATIC
Which of the following sentences is a description of the median of a data set for a variable?
The median is the data value that lies in the middle of the data when the data is arranged in ascending order.
Determine whether the statement is true or false. If it is false, rewrite it as a true statement. It is impossible to have a z-score of 0.
The statement is false. A z-score of 0 is a standardized value that is equal to the mean.
Is the variable discrete or continuous? Temperature on a randomly selected day in your home town
The variable is continuous because it is not countable
is the variable discrete or continuous? Number of notes in a song
The variable is discrete bc it is countable.
What type of sample is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.
a cluster sample
The _________________ is the difference between consecutive lower class limits.
class width
To determine customer opinion of their inflight service, Continental Airlines randomly selects 130 flights during a certain week and surveys all passengers on the flights. What type of sampling is used here?
cluster sampling
A newspaper asks its readers to call in their opinion regarding the number of books they have read this month. What type of sampling is used?
connivence sampling
True or False: A data set will always have exactly one mode.
false
The ______ class limit is the smallest value within the class and the ______ class limit is the largest value within the class.
lower; upper
is a numerical summary of a population.
parameter
Sx =
sample standard deviation.
IBM wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 80 customers and asks them about their level of satisfaction with the company. What type of sampling is used here?
simple random
is a numerical summary of a sample.
statistic
what type of sample is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group.
stratified sample
In a frequency distribution, the class width is the distance between ________?
the lower or upper limits of consecutive classes.
Determine whether the statement is true or false. If it is false, rewrite it as a true statement. A data set can have the same mean, median, and mode.
the statement is true
The _______ represents the number of standard deviations an observation is from the mean.
z - score
what is the formula for z-score?
z = (x - μ)/σ