Answer:
64
Step-by-step explanation:
Let us consider E_abc to be the event that a, b and c appear on the first, second and third slot of the spin machine.
Now, we are told that each slot has 4 possibilities which are a cherry, a lemon, a star, or a bar when spun.
Thus, from mn rule in probability, the total number of simple events in the sample space is = 4³ = 64
Answer: …………..
Step-by-step explanation:
……………..
Answer:
The length of AB is 7.45 units.
Step-by-step explanation:
You can find the length of AB using Cosine Rule, cosθ = adj./hypo. :
θ = 20°
adj. = 7 units
hypo. = AB
cos 20° = 7/AB
AB = 7/cos 20°
= 7.45 units (3s.f)
Answer:
Step-by-step explanation:
Let's find the volume of the room in ft³ and that will give
14×22×9=2772ft³
There are deductions. Hence we subtract them from this value
3×5=15, but there are two, hence 15×2=30ft²
And 4×7=28ft²
Hence 2772-(30+28)=2714
Dividing this value by 320 gives
8.4(to 2s.f)
Let's call our estimate x. It will be the average of n IQ scores. Our average won't usually exactly equal the mean 97. But if we repeated averages over different sets of tests, the mean of our estimate the average would be the same as the mean of a single test,
μ = 97
Variances add, so the standard deviations add in quadrature, like the Pythagorean Theorem in n dimensions. This means the standard deviation of the average x is
σ = 17/√n
We want to be 95% certain
97 - 5 ≤ x ≤ 97 + 5
By the 68-95-99.7 rule, 95% certain means within two standard deviations. That means we're 95% sure that
μ - 2σ ≤ x ≤ μ + 2σ
Comparing to what we want, that's means we have to solve
2σ = 5
2 (17/√n) = 5
√n = 2 (17/5)
n = (34/5)² = 46.24
We better round up.
Answer: We need a sample size of 47 to be 95% certain of being within 5 points of the mean
