1. The problem is to determine whether each given statement about normal distribution, hypothesis testing, and probability is ALWAYS, SOMETIMES, or NEVER true.
2. Let's analyze each statement carefully:
- "The parameters to be considered in normal distribution are the population mean and the standard score."
The parameters of a normal distribution are the population mean ($\mu$) and the population standard deviation ($\sigma$), not the standard score (z-score). The standard score is derived from these parameters.
**Answer: NEVER**
- "If the graph of a normal curve is shorter and wider, the standard deviation has greater value."
A larger standard deviation spreads the curve out more, making it wider and lower in height.
**Answer: ALWAYS**
- "If the element is 25, population mean is 25, and standard deviation is 10. The area will be equal to zero."
The area under the normal curve at a single point is zero because area represents probability over an interval.
**Answer: ALWAYS**
- "The standard score of zero will produce an area equal to zero."
A z-score of zero corresponds to the mean; the probability at a single point is zero, but cumulative area up to zero is 0.5.
The statement is ambiguous but if it means area at that point, it's zero.
**Answer: ALWAYS**
- "The baseline of a normal curve is a number line with 6 sigma distances."
The normal distribution is often shown with a range of $\pm 3\sigma$ (total 6 sigma distances) covering most data.
**Answer: SOMETIMES** (commonly used but not a strict rule)
- "A hypothesis statement is a prediction or an educated guess."
Hypothesis is a testable prediction.
**Answer: ALWAYS**
- "The alternative hypothesis should always be accepted."
Alternative hypothesis is accepted only if data supports it.
**Answer: NEVER**
- "The null hypothesis should always be rejected."
Null hypothesis is rejected only if evidence is strong.
**Answer: NEVER**
- "In tossing a coin, the result will always be pair and balance."
Single toss can be heads or tails; no guarantee of balance.
**Answer: NEVER**
- "In tossing 10 coins, the result will always be pair and balance."
Results vary; balance is not guaranteed.
**Answer: NEVER**
3. Summary of answers:
| Statement | Truth Value |
|---|---|
| Parameters are mean and standard score | NEVER |
| Shorter and wider curve means greater SD | ALWAYS |
| Area at element = mean is zero | ALWAYS |
| Z-score zero area is zero | ALWAYS |
| Baseline is number line with 6 sigma | SOMETIMES |
| Hypothesis is prediction | ALWAYS |
| Alternative hypothesis always accepted | NEVER |
| Null hypothesis always rejected | NEVER |
| Tossing coin always pair and balance | NEVER |
| Tossing 10 coins always pair and balance | NEVER |
Final answers are based on statistical definitions and probability theory.
Truth Statements
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