A campus radio station surveyed 500 students to determine the types of music they like. the survey revealed that 199 like rock,
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If the shape on the red image is scaled to the shape on the blue image, the scale factor is 0.2777.
Explanation:
- The original shape's base in the red image is measured. The base of the red image is measured to be 9 units. Now we measure the same side of the blue image. The base of the blue image is measured to be 2.5 units. So after scaling, the length of the painting will be 2.5 units.
- To calculate the scale factor, we divide the measurement after scaling by the same measurement before scaling. In this case, it is the base of both images. So The scale factor =
=
= 0.2777.
- So the red image is dilated by a scale factor of 0.2777 to produce the blue image.
Answer:
The bulbs should be replaced each 1436.9 hours.
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:
How often should the bulbs be replaced so that no more than 1% burn out between replacement periods?
This is the first percentile of hours. So it is X when Z has a pvalue of 0.01.
So it is X when Z = -2.33.
The bulbs should be replaced each 1436.9 hours.