A Z-score helps us to understand how far is the data from the mean. The correct option is C.
A Z-score helps us to understand how far is the data from the mean. It is a measure of how many times the data is above or below the mean. It is given by the formula,
[tex]Z = \dfrac{X- \mu}{\sigma}[/tex]
Where Z is the Z-score,
X is the data point,
μ is the mean and σ is the standard variable.
The Percentage of butterflies that weights 53 gram and below,
P(X≤53) = P[ Z ≤ (53 - 50)/3}
= P(Z ≤ 1)
= 0.8413
The Percentage of butterflies that weights 47 gram and below,
P(X≤47) = P[ Z ≤ (47- 50)/3}
= P(Z ≤ -1)
= 0.1587
Now, the percentage of the butterflies weigh between 47 grams and 53 grams is,
P(53 ≤ x ≤ 47) = P(X≤53) - P(X≤47)
= 0.8413 - 0.1587
= 0.6826
= 68%
Hence, the correct option is C.
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