Answer:
9,676,800
Step-by-step explanation:
Using the t-distribution, it is found that:
a. The <u>margin of error</u> is of 4.7 homes.
b. The 98% confidence interval for the population mean is (19.3, 28.7).
The information given in the text is:
- Sample mean of
. - Sample standard deviation of
. - Sample size of
.
We are given the <u>standard deviation for the sample</u>, which is why the t-distribution is used to solve this question.
The confidence interval is:

The margin of error is:

Item a:
The critical value, using a t-distribution calculator, for a two-tailed <u>98% confidence interval</u>, with 23 - 1 = <u>22 df</u>, is t = 2.508.
Then, the <em>margin of error</em> is:

Item b:
The interval is:


The 98% confidence interval for the population mean is (19.3, 28.7).
A similar problem is given at brainly.com/question/15180581
Answer:
Step-by-step explanation:
Given that in 1987, the population of country A was estimated at 87 million people, with an annual growth rate of 3.5%
Thus the equation for population for country A would be

The 1987 population of country B was estimated at 243 million with an annual growth rate of 0.6%.
So equation for population for country B would be
where t = time in years and P in millions
a) P(A) = 2*87 when

Take log and solve
ln 2 = 0.005 t
t = 138.63
Thus after 138 years population will double for A
b) P(A) = P(B) when

Approximately after 35.5 years the populations of both countries would be equal.
Step-by-step explanation:
For a quadratic equation y = ax² + bx + c, the vertex (the maximum or minimum point) is at x = -b/(2a).
1) y = -0.5t² + 2t + 38
The maximum is at:
t = -2 / (2 × -0.5)
t = 2
The maximum height is:
y = -0.5(2)² + 2(2) + 38
y = 40
The coordinates of the vertex are (2, 40). That means the missile reaches a maximum height of 40 km after 2 minutes.
2) y = -4.9t² + 12t + 1.6
The maximum is at:
t = -12 / (2 × -4.9)
t = 1.22
The maximum height is:
y = -4.9(1.22)² + 12(1.22) + 1.6
y = 8.95
The coordinates of the vertex are (1.22, 8.95). That means the missile reaches a maximum height of 8.95 m after 1.22 seconds.
3) y = -0.04x² + 0.88x
The maximum is at:
x = -0.88 / (2 × -0.04)
x = 11
The maximum height is:
y = -0.04(11)² + 0.88(11)
y = 4.84
The maximum height of the tunnel is 4.84 meters.
The maximum width is when y = 0.
0 = -0.04x² + 0.88x
0 = -0.04x (x − 22)
x = 22
The maximum width is 22 feet.