Answer :
Final answer:
The first (D1-10th percentile) and last (D9-90th percentile) deciles of the standard normal distribution, which divides the distribution into ten equal parts, are -1.28 and 1.28 respectively.
Explanation:
The question is about the first and last deciles of the standard normal distribution, which is a statistical distribution that has a mean of 0 and a standard deviation of 1. The deciles of a distribution are the points that divide it into ten equal parts. The first decile (D1) is the 10th percentile and the last decile (D9) is the 90th percentile.
On a standard normal distribution table, the score representing the 10th percentile is -1.28 and the score representing the 90th percentile is 1.28. Therefore, the first and last deciles of the standard normal distribution are -1.28 and 1.28. So, Option 1 is correct.
Learn more about Standard Normal Distribution here:
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