Tom bought 3 boxes of 8 chocolate bars for a party, and laura had 17 bars more.Which equation could be solved to find how many c
2 answers:
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Answer:
Step-by-step explanation:
There can be two values of x.
The range is largest no. - smallest no.
Range = 64
Let x be the smallest no.
largest no. from the list is 37
37 - x = 64
-x = 64 - 37
x = -27
Let x be the largest no.
smallest no. from the list is 3
x - 3 = 64
x = 64 + 3
x = 67
Answer:
31.92% probability that 18 randomly selected bulbs would have an average life of no more than 260 days
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
When the distribution is normal, we use the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean and standard deviation
In this question, we have that:
What is the probability that 18 randomly selected bulbs would have an average life of no more than 260 days?
This is the pvalue of Z when . So
By the Central Limit Theorem
has a pvalue of 0.3192.
31.92% probability that 18 randomly selected bulbs would have an average life of no more than 260 days