The mean of a dataset is 15 and the standard deviation is 3. What percentage of data points lie within 12 and 18?
Cannot be determined from the given information
Approximately 99.7%
Approximately 95%
Approximately 68%
Which of the following correctly describes the null and alternative hypotheses?
The null hypothesis assumes a relationship, while the alternative hypothesis denies it.
The null hypothesis represents the status quo or no effect, while the alternative hypothesis proposes a specific effect.
The null and alternative hypotheses are interchangeable.
The null hypothesis is what we aim to prove, and the alternative hypothesis is the opposite.
Which type of error occurs when we reject a true null hypothesis?
Type II error
Sampling error
Type III error
Type I error
What is the primary difference between a discrete probability distribution and a continuous probability distribution?
There is no difference; both types of distributions represent the same statistical concepts.
Discrete distributions are represented by graphs, while continuous distributions are represented by tables.
Discrete distributions deal with countable data, while continuous distributions deal with data that can take on any value within a range.
Discrete distributions are used for quantitative data, while continuous distributions are used for qualitative data.
What does a variance of zero indicate about a dataset?
The dataset has a large amount of variation.
All data points are the same.
The data is perfectly normally distributed.
The mean is zero.
Every 10th person entering a store is surveyed about their shopping experience. What type of sampling method is being used?
Cluster Sampling
Simple Random Sampling
Stratified Sampling
Systematic Sampling
Which of the following best describes a Type II error?
Rejecting the alternative hypothesis when it is actually true.
Rejecting the null hypothesis when it is actually true.
Accepting the alternative hypothesis when it is actually false.
Failing to reject the null hypothesis when it is actually false.
Which data type is represented by the ranking of athletes in a competition (1st, 2nd, 3rd, etc.)?
Nominal
Interval
Ordinal
Ratio
A researcher wants to ensure representation from different age groups (20-30, 31-40, 41-50, etc.) in their sample. Which sampling method is most appropriate?
Descriptive statistics primarily deals with:
Summarizing and visualizing existing data
Testing hypotheses about population parameters
Drawing conclusions about populations from samples
Predicting future outcomes based on data trends