While wandering in jungle, King Dushyant married Shankuntala as narrated in the "Abhigyan Shankuntalam". He gave her royal ring which could serve her identity when she would come to meet him, in future. However, she had lost the ring while going to meet him. When she arrived at Dushyant's palace, he failed to recognise her as she did not had the ring. Which of the following statistical error King Dushyant had committed in this narrative?
Type I errors
This question asks us to identify the type of statistical error King Dushyant committed based on the narrative from "Abhigyan Shankuntalam". The core issue is King Dushyant's failure to recognize Shakuntala because she lacked the royal ring, which was the expected proof of her identity as his wife.
In statistics, particularly in hypothesis testing, we make decisions based on data. There's always a possibility of making an incorrect decision. These incorrect decisions are classified into two main types of errors:
Let's look at the possible outcomes of a hypothesis test:
| Actual Situation | Decision based on test | Outcome |
|---|---|---|
| $H_0$ is True | Fail to Reject $H_0$ | Correct Decision |
| $H_0$ is True | Reject $H_0$ | Type I Error |
| $H_0$ is False | Fail to Reject $H_0$ | Type II Error |
| $H_0$ is False | Reject $H_0$ | Correct Decision |
Let's frame the situation in the narrative in terms of hypothesis testing:
King Dushyant used the presence of the royal ring as his test or criterion. His decision rule was essentially:
Now, let's consider the reality and the King's decision:
Comparing the Actual Situation ($H_0$ is True) with the Decision (Reject $H_0$), we see that the King rejected a true null hypothesis.
This matches the definition of a Type I error.
If it had been a Type II error, it would mean Shakuntala was *not* his wife ($H_0$ is false), but he incorrectly recognized her anyway (failed to reject $H_0$). That is not what happened in the story.
In the narrative, King Dushyant's condition for recognition was the presence of the royal ring. When the ring was absent, he concluded she was not his wife, despite the fact that she truly was. Rejecting the true null hypothesis (that she is his wife) because the evidence (the ring) was missing constitutes a Type I error.
| Error Type | Description | Analogy in Narrative |
|---|---|---|
| Type I Error ($\alpha$) | Rejecting a true $H_0$ (False Positive) | Rejecting that Shakuntala is wife ($H_0$ True) |
| Type II Error ($\beta$) | Failing to reject a false $H_0$ (False Negative) | Failing to reject that Shakuntala is wife ($H_0$ False) - Not the case here. |
Hypothesis testing is a fundamental concept in statistics used to make inferences about a population based on sample data. It involves setting up two competing hypotheses:
The process involves collecting data, performing a statistical test, and calculating a p-value. The p-value is the probability of observing data as extreme as, or more extreme than, the sample data, assuming the null hypothesis is true. Based on the p-value and a chosen significance level ($\alpha$), we decide whether to reject or fail to reject the null hypothesis.
The significance level ($\alpha$) is the maximum acceptable probability of committing a Type I error. Common values for $\alpha$ are 0.05 (5%) or 0.01 (1%). There is a trade-off between Type I and Type II errors; reducing the probability of one type of error often increases the probability of the other, for a fixed sample size.
Type II error in hypothesis testing is:
Which level of measurement is least used in educational psychology?
In List I types of variables are given and in List II correlation coefficients related to them are given. Match List I and List II and choose the correct answer from the code given below.
List I (Types of variable) | List II (Correlation coefficient) | ||
| a) | Both variables continuous | i) | Biserial |
| b) | Both with ordinal measure | ii) | Pearson's 'r' |
| c) | Both with artificial dichotomy | iii) | Contingency coefficient |
| d) | One continuous and other with artificial dichotomy | iv) | Spearman's rho |
| e) | Two or more categories | v) | Tetrachoric 'r' |
| vi) | Point-Biserial | ||
Match the measurement scales in Set I with the examples in Set II.
Set I
(a) Nominal scale
(b) Ordinal scale
(c) Interval scale
(d) Ratio scale
Set II
(i) Ranking students’ performances in musical events
(ii) Spelling-test scaled scores defined with equal units and an arbitrary zero
(iii) Classifying students by the type of co-curricular activity they participate in
(iv) Students’ writing speed in words per minute
For scores drawn from a continuous reference distribution, what is the shape of the distribution of their percentile ranks?