Commerce MCQs
Topic Notes: Commerce
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
181
Which statistical test is primarily utilized to determine the goodness of fit of a distribution?
Answer:
Chi-square test
The Chi-square test is a non-parametric test used to determine if there is a significant difference between the expected frequencies and the observed frequencies in one or more categories. It is the standard method for testing the 'goodness of fit,' which assesses how well an observed data distribution matches a theoretical or expected distribution.
182
When sample evidence leads to the rejection of the null hypothesis, what is the term for the statement that is accepted in its place?
Answer:
alternative hypothesis
In hypothesis testing, the alternative hypothesis (H1 or Ha) is the statement that is accepted as true when the null hypothesis (H0) is rejected based on statistical evidence from the sample data.
183
Which statement regarding the Central Limit Theorem is considered incorrect?
Answer:
If the population is not normal from which the sample is drawn, the SDM is not normal for any sample size
The Central Limit Theorem states that as the sample size increases, the sampling distribution of the sample mean approaches a normal distribution, regardless of the shape of the population distribution. Option C is incorrect because it denies this convergence, which is the core principle of the theorem. The theorem allows statisticians to make inferences about population parameters even when the underlying population distribution is unknown or non-normal.
184
Which statistical test is appropriate for analyzing data when the sample size is small?
Answer:
t-test
The t-test, developed by William Sealy Gosset, is specifically designed for small sample sizes (typically n < 30) where the population standard deviation is unknown. It provides a more accurate estimation of the population mean compared to the z-test, which is better suited for larger samples.
185
Given a sum of squares within samples of 140 (12 degrees of freedom) and between samples of 190 (2 degrees of freedom), what is the F-test statistic?
Answer:
8.14
The F-statistic is calculated as the ratio of the Mean Square Between (MSB) to the Mean Square Within (MSW). MSB = 190 / 2 = 95. MSW = 140 / 12 = 11.666. F = 95 / 11.666 = 8.14. This statistic is used in ANOVA to determine if group means are significantly different.
186
What factors determine the required sample size in statistical research?
Answer:
Both A and B
Sample size determination is primarily driven by the desired precision, represented by the margin of error, and the level of confidence required, represented by the confidence coefficient (z-score). A smaller margin of error or a higher confidence level necessitates a larger sample size to ensure the results are statistically representative and reliable.
187
The critical region in a hypothesis test is defined by which of the following probabilities?
Answer:
probability of committing type I error
The critical region (or rejection region) is the set of values of the test statistic for which the null hypothesis is rejected. The size of this region is equal to the significance level, which represents the probability of committing a Type I error.
188
What is the statistical term for failing to reject a null hypothesis when it is actually false?
Answer:
type II error
A Type II error occurs when a statistical test fails to reject a null hypothesis that is false in reality. This is often referred to as a 'false negative' result, where the researcher misses a true effect.
189
The level of significance represents the probability of committing which type of error?
Answer:
type I error
In hypothesis testing, the level of significance (denoted by alpha) is defined as the probability of rejecting the null hypothesis when it is actually true. This is formally known as a Type I error.
190
What is the standard deviation of the sampling distribution of the mean specifically called?
Answer:
standard error of the mean
The standard error of the mean (SEM) measures how far the sample mean of the data is likely to be from the true population mean. It is calculated by dividing the population standard deviation by the square root of the sample size. It is a fundamental concept in inferential statistics used to determine the precision of the sample mean as an estimate.