Work shown above! Answer is p = 4, -5 , 3
A Z-score helps us to understand how far is the data from the mean. The number of phones who have battery life in the range of 11.4 to 13 range is 1145.
<h3>What is Z-score?</h3>
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,

Where Z is the Z-score,
X is the data point,
μ is the mean and σ is the standard variable.
The percentage of phones who have battery life in the range of 11.4 to 13 range is,

= 0.50 - 0.0228
= 0.4772
Now, the number of phones who have battery life in the range of 11.4 to 13 range is,
Number of phones = 0.4772 × 2400 = 1145.28 ≈ 1145
Hence, the number of phones who have battery life in the range of 11.4 to 13 range is 1145.
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Answer:
And we can find this probability using the normal standard table or excel:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the amount of ml of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the normal standard table or excel:
Answer:
240 is the answer
Step-by-step explanation:
Answer:
19.5
Step-by-step explanation:
78÷4
=39÷2
=19.5
The Answer is 19.5