Means
What type of error occurs if we reject a true null hypothesis when performing a test for a population mean?
Non-sampling Error
Sampling Error
Type I Error
Type II Error
What indicates that an observed sample mean could be an outlier in terms of its effect on setting up tests for population means?
It lies outside essentially all previously observed values within similar studies.
It falls within one standard deviation from other observed values in similar studies.
It matches closely with more than half of other observed values in previous researches.
It shows no significant statistical difference from other previously obtained means.
What does it mean for a sample to be random in the context of statistical tests?
The sample was chosen without any specific criteria.
The sample was chosen randomly to mirror the population.
The sample was collected over a long period of time.
The sample was selected from a large population.
In testing for differences between two means with independent samples where variances are unknown but assumed equal, what test statistic should be used?
Z-test statistic
Pooled variance t-test statistic
Unpooled variance t-test statistic
Chi-square test statistic
When planning a test for a population mean, why is it important to consider the variability of the sample data?
Variability has no impact on determining which test statistic to use.
Lower variability always ensures that the null hypothesis will be rejected.
A higher variability may increase the standard error and widen the confidence interval.
Increased variability reduces the likelihood of Type I errors.
How does increasing alpha level from 0.05 to 0.10 affect type I errors and statistical power in hypothesis testing?
Decreases type I errors but increases statistical power.
Increases type I errors but has no effect on statistical power.
Both type I errors remaining unchanged, and statistical power remains the same as well.
Increases type I errors and also increases statistical power.
Which of these denotes the alternative hypothesis in a one-sided test?
Both populations have identical standard deviations.
The sample mean equals some known value.
The population mean is less than or greater than some value.
There are no differences between groups being tested.

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When testing an alternative hypothesis that states there has been an increase in response time after implementing new software at customer service centers nationally, what kind of test would you use?
Two-tailed test
One-tailed test
Independent samples t-test
Paired samples t-test
How is a two-tailed hypothesis test setup differently from a one-tailed hypothesis test regarding the alternative hypothesis?
The alternative states that the parameter is simply not equal to a specific value ()
Alternative hypotheses for two-tailed tests are never expressed in terms of inequality ( or )
In the two-tailed test, the alternative hypothesis states the parameter is smaller than a value ()
The two-tailed alternative hypothesis argues the parameter is larger than a value ()
Which condition checks if the sampling distribution of the sample mean is approximately normal?
Population is given to be approximately normal.
Distribution of sample data looks approximately symmetric with no apparent outliers or gaps.
All the answer choices
Central Limit Theorem (sample size is at least 30)