Answer:
The standard error of the mean is 4.5.
Step-by-step explanation:
As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:

The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.
The mean of the sample is:

The standard deviation of the sample is calculated as:

Then, we can calculate the standard error of the mean as:

Answer:
Final cost = £779
Step-by-step explanation:
It is given that:
Cost of summer holiday = £650
Amount increased by 11%
Increased cost = 11% of 650
Increased cost = 
Increased cost = 0.11 * 650 = £71.50
Amount after increment = 650 + 71.50 = £721.50
Further increase = 8%
Amount = 0.08 * 721.50 = £57.72
Final cost = 721.50 + 57.72 = £779.22
Thus,
Final cost = £779
Answer:
f(x) = - 4x² + 24x - 20
Step-by-step explanation:
Given
f(x) = - 4(x - 3)² + 16 ← expand the factor using FOIL
= - 4(x² - 6x + 9) + 16 ← distribute parenthesis by - 4
= - 4x² + 24x - 36 + 16 ← collect like terms
= - 4x² + 24x - 20
Answer:
9
Step-by-step explanation:
8X+4=360-108-80-96
8X+4=76
8X=76-4
8X=72
X=72/8
X=9