The button on Keith's shirt has a radius of 3 cm.
1 answer:
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Answer:
Step-by-step explanation:
The easier way to figure this is by using the concept of torque in physics. If the torque of the man is greater than that experienced by the box, the lever will tilt in the man's favor (in other words, he will move down and the box will be lifted). Torque is found by multiplying the perpendicular force by the length of the lever arm. Because we want the man's torque to be greater than the box's torque, the inequality is:
and
That decimal is 6 inches in terms of meters.
180r > 76.2 so
r > .42 meters or `16.67 inches. The man has to sit at a distance greater than 16.67 inches in order for the box to be lifted by the lever.
Answer:
5.05% probability that no more than 34% had received such an email.
Step-by-step explanation:
We use the binomial approximation to the normal to solve this problem.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
Can be approximated to a normal distribution, using the expected value and the standard deviation.
The expected value of the binomial distribution is:
The standard deviation of the binomial distribution is:
Normal probability distribution
Problems of normally distributed samples can be 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.
When we are approximating a binomial distribution to a normal one, we have that ,
.
In this problem, we have that:
In a random sample of 700 adults, what is the probability that no more than 34% had received such an email?
34% is 0.34*700 = 238
So this probability is the pvalue of Z when X = 238.
has a pvalue of 0.0505
5.05% probability that no more than 34% had received such an email.