answers to Statistics unit test

Answer 1

1. Statistical inference is the process of drawing conclusions about a population based on sample data.

2. A parameter is a numerical characteristic of a population, while a statistic is a numerical characteristic of a sample.

3. Null hypothesis (H0): a statement that there is no effect or relationship in the population. Alternative hypothesis (Ha): a statement that there is an effect or relationship in the population.

4. Type I error: rejecting a true null hypothesis. Type II error: failing to reject a false null hypothesis.

5. The p-value is the probability of observing a test statistic as extreme as the one calculated, assuming the null hypothesis is true. A smaller p-value indicates stronger evidence against the null hypothesis.

6. Confidence interval is a range of values that likely contain the true population parameter with a specified level of confidence.

7. Sampling error is the difference between a sample statistic and the population parameter it estimates. It is due to sampling variability.

8. The Central Limit Theorem states that as sample size increases, the distribution of sample means approaches a normal distribution, regardless of the shape of the population distribution.

9. Correlation coefficient (r) measures the strength and direction of a linear relationship between two variables. It ranges from -1 to 1, with 1 indicating a perfect positive correlation, -1 indicating a perfect negative correlation, and 0 indicating no correlation.

10. Regression analysis is a statistical technique used to examine the relationship between one dependent variable and one or more independent variables. It is used to predict the value of the dependent variable based on the values of the independent variables.