Write an exponential function to model the situation.A population of 300 animals decreased at an annual rate of 22%
1 answer:
Answer:
Step-by-step explanation:
x is the number of years. y is the population after x years.
Each year, the population decreases by 22%, since 100% - 22% = 78%, and 78% = 0.78, each year, the population is 0.78 of the previous year's population.
year zero: y = 300
year 1: y = 300 * 0.78 = 300 * (0.78)^1
year 2: y = (300 * 0.78) * 0.78 = 300 * (0.78)^2
year 3: y = ((300 * 0.78) * 0.78) * 0.78 = 300 * (0.78)^3
year x: y = 300(0.78)^x
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Answer:
And we can find this probability using excel or the normal standard tabe and we got:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the temperatures of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using excel or the normal standard tabe and we got: