3 years ago

Cindys grandmother is five times her age. Find each of their ages if the sum of their ages is 90

Mathematics

1 answer:

yan [13]3 years ago

6 0

Answer:

cindy=15 grandmother=75

Step-by-step explanation:

90 divide 6 equal to 15

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Five students visiting the student health center for a free dental examination during National Dental Hygiene Month were asked h

Andrews [41]

Answer:

[0.9 months, 32.69 months]

Step-by-step explanation:

The mean is

$\bf \bar x=\frac{5+17+12+21+29}{5}=16.8$

The standard deviation is

$\bf s=\sqrt{\frac{(5-16.8)^2+(17-16.8)^2+(12-16.8)^2+(21-16.8)^2+(29-16.8)^2}{5}}=8.1092$

Now, we have to find two values a and b such that the area under the Normal curve with mean 16.8 and standard deviation 8.1092 between a and b equals <em>95% = 0.95 </em>

Using a spreadsheet we find these values are

a = 0.906

b = 32.694

<h3>(See picture) </h3>

and our 95% confidence interval for the mean number of months elapsed since the last visit to a dentist for the population of students participating in the program rounded to two decimal places is

[0.9 months, 32.69 months]