The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of
2 answers:
Answer:
2.28% probability that it will weigh less than 900 grams
Step-by-step explanation:
Problems of normally distributed samples are solved using 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.
In this problem, we have that:
What is the probability that it will weigh less than 900 grams?
This probability is the pvalue of Z when X = 900. So
has a pvalue of 0.0228.
2.28% probability that it will weigh less than 900 grams
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Answer:
And we can find the individual probabilities using the probability mass function
And replacing we got:
Step-by-step explanation:
Previous concepts
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
Solution to the problem
Let X the random variable of interest "number of automobiles with both headligths working", on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
And for this case we want to find this probability:
And we can find the individual probabilities using the probability mass function
And replacing we got: