Answer:
the probability that a sample of the 35 exams will have a mean score of 518 or more is <em> 0.934 </em>or<em> 93.4%</em>.
Step-by-step explanation:
This is s z-test because we have been given a sample that is large (greater than 30) and also a standard deviation. The z-test compares sample results and normal distributions. Therefore, the z-statistic is:
(520 - 518) / (180/√35)
= 0.0657
Therefore, the probability is:
P(X ≥ 0.0657) = 1 - P(X < 0.0657)
where
- X is the value to be standardised
Thus,
P(X ≥ 0.0657) = 1 - (520 - 518) / (180/√35)
= 1 - 0.0657
= 0.934
Therefore, the probability that a sample of the 35 exams will have a mean score of 518 or more is <em>0.934 or 93.4%</em>.
7 3/4 × 3/4 = So u add 3×3=9
Then add 4×4=16 Give you 9/16
Then you add that 7 you left out with 9/16
But just the 9 not the 16
7 × 9 = 63 And your answer is 63/16
Hope i help :-)
Answer: D
Step-by-step explanation:
Is if you do 18-5=13 13 is what Toby scored
First, let's construct an algebraic equation to formally find the answer:
Let x represent (the value of) the unknown number.
x²= 5x + 24 --- This equation shows that the (positive) number's square equals 24 more than 5 times the number.
Now we can solve for x (the number):
x² = 5x + 24
x² - 5x - 24 = 0
(x + 3)(x - 8) = 0
x = -3, 8
Therefore, this means that x (the number ) can be either -3 OR 8. Both will satisfy the description.
Hope this helps!
Answer:
Step-by-step explanation:
The mean of the gas mileages is 317÷16=19.8125
317 is the sum total of all the figures and 16 is the number of figures in the distribution
Standard deviation is the square root of the variance and the variance is the mean of all squared deviations
The 16 squared deviations are
7.9102(×2) + 3.2852(×2) + 0.6602(×3) + 0.0352(×4) + 1.4102(×3) + 10.1602 + 17.5352 = 56.4382
56.4382÷16 = 3.5274
This is the Variance. The standard deviation is herefore √3.5274 =1.878 ~ 1.88 (to 2 decimal places)
(B) Chebyshev's inequality predicts that 75% of the selection will fall within 2 standard deviations of the mean
2×1.88=3.76
19.8125-3.76 = 16.05
19.8125+3.76= 23.57
The gas mileages are between 16.05 and 23.57
(C) the actual % of SUV models of the sample that fall in the above range is (15/16 × 100) = 93.75%
(D) the empirical rule gives the more accurate prediction
