Answer:
(-8, 8)
Step-by-step explanation:
Plug in the y from the top equation into the y of the bottom equation
x² + (x + 16)² = 128
x² + x² + 32x + 256 = 128
Subtract 128 from both sides to make it equal to zero
2x² + 32x + 256 = 128
- 128 - 128
2x² + 32x + 128 = 0
Divide both sides by 2
(2x² + 32x + 128)2 = 0/2
x² + 16x + 64 = 0
Factor the equation
(x + 8)(x + 8) = 0
We see that x will have to be -8 for it to equal zero
so x = -8
Plug the new x into one of the original equations; let's use the top one
y = -8 + 16
y = 8
Answer:
For this case we need to check the conditions in order to use the normal approximation:
1)
2)
Since both conditions are satisfied and the independence condition is assumed we can use the normal approximation given by:
The mean would be given by:
And the deviation is given by:
Step-by-step explanation:
For this case we know the following info:
n =60 represent the sample size
represent the estimated proportion of people that will buy a packet of crackers after tasting
For this case we need to check the conditions in order to use the normal approximation:
1)
2)
Since both conditions are satisfied and the independence condition is assumed we can use the normal approximation given by:
The mean would be given by:
And the deviation is given by:
Answer:
a? sorry if it wrong
Step-by-step explanation:
Answer:
Step-by-step explanation:
We want to determine a 90% confidence interval for the mean amount of time that teens spend online each week.
Number of sample, n = 41
Mean, u = 43.1 hours
Standard deviation, s = 5.91 hours
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
43.1 ± 1.645 × 5.91/√41
= 43.1 ± 1.645 × 0.923
= 43.1 ± 1.52
The lower end of the confidence interval is 43.1 - 1.52 =41.58
The upper end of the confidence interval is 43.1 + 1.52 =44.62
Therefore, with 90% confidence interval, the mean amount of time that teens spend online each week is between 41.58 and 44.62
Answer:
72 seconds
Step-by-step explanation:
0.24 feet in a second
0.24 ft. x 300 = 72
72 seconds