The probability of 6 years or more, so we want the complement,
1 - 0.98533 = 0.01467 1.467% chance, not very likely.
<h3>What is Z-score?</h3>
A z score is a type of statistical measurement that gives an idea of how far a raw score is from the mean of a distribution. A z score is used in a z test for hypothesis testing.
Here, Because you are looking for the mean of a group of 7.8, the standard deviation will shrink by a factor of √6
Old standard deviation = 0.7,
new standard deviation = 0.7/√6 = 0.64254
You need to find a z-score and then convert your z-score to a probability.
z-score = (your score - average)/ std dev
z-score = (7.8 - 6)/0.64254
z-score = 2.1789
To convert a z-score either look it up on a table or use a calculator.
But z-tables are designed to shade to the left, which means this is the probability that the mean life is 6 years or less. We want the probability of 6 years or more, so we want the complement, 1 - 0.98533 = 0.01467
1.467% chance, not very likely.
Learn more about Z-score from:
brainly.com/question/15016913
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