Normal Curve and Area
The standard normal curve has a mean of _____ and a standard deviation of _________
What is mean =0 and standard deviation =1
Find a point estimate for p if 24 out of 100 drivers at fault in fatal accidents were inadequately insured.
What is 0.24?
The null and alternative hypotheses are H₀: μ = 9.5, H₁: μ ≠ 9.5. Is this test left-tailed, right-tailed, or two-tailed?
What is 2 Tailed?
Make a scatter diagram for the data: x = 3, 8, 6, 5, 9, 4; y = 4, 7, 5, 5, 6, 3. How are the variables related?(positive, negative AND linear, nonlinear)
What is Positively, linearly related?
A box contains 27 red marbles, 33 white marbles, and 85 blue marbles. What is the probability of selecting a red marble?
27/(27+33+85) = 27/145 ≈ 0.186
True or False: The area under the normal curve drawn with regard to the population parameters is the same as the probability that a randomly selected individual of a population has these characteristics.
What is TRUE
Estimate the proportion of all teenagers who want more family discussions about school. Use a 99% confidence level and p = 0.37, n = 522.
What is 0.37 ± 0.054?
If we reject the null hypothesis when it is actually true, what type of error have we made?
What is Type I error?
Explain what it means to have a correlation of +1
r=1
What is a perfect positive correlation?
What is the probability of rolling a sum of 9 on a standard pair of six-sided dice?
4/36 = 1/9 ≈ 0.111
Find the area under the standard normal curve to the left of z = 1.5.
What is 0.9332
Determine the point estimate of the population mean and margin of error for the confidence interval with lower bound 19 and upper bound 27.
What is ) x̄ = 23, E = 4?
Find the critical value for a two-tailed test with α = 0.10.
What is ±1.645?
A researcher finds a linear correlation coefficient of 0.85 for a paired data set. What does this indicate?
What is a Strong positive linear correlation?
There are 720 chips numbered 1–720. What is the probability of drawing a chip numbered less than 569?
568/720 ≈ 0.789
Find the area under the standard normal curve between z = 0 and z = 3.
What is 0.4987
Construct a 95% confidence interval for the population mean, μ, with sample mean $3120, s = $677, n = 20.
What is ($2803, $3437)?
A pizza restaurant tests if mean delivery time exceeds 34 minutes. If p-value = 0.0290, what is the correct conclusion at α = 0.05?
At α=0.05, reject H₀
Calculate the linear correlation coefficient for:
x = -11, -9, -2, -5, -7, -8, -6, -4, -3, -10;
y = -5, -3, 14, 6, 3, -1, 4, 8, 11, -3.
What is 0.990?
Determine whether choosing a heart or a black card from a deck is mutually exclusive.
No (hearts are red, so yes, mutually exclusive)
A physical fitness association finds boys’ mile run times are normally distributed with mean 440 sec and σ = 40 sec. What is the probability a randomly selected boy runs the mile in less than 348 seconds?
0.0107
The FDA tests a new cigarette with mean nicotine content 28.5 mg, s = 2.2 mg, n = 9. Does the data support the claim that mean nicotine content exceeds 31.2 mg at 95% confidence?
No, since 31.2 does not fall in the 95% CI
The business college computing center wants to determine if the proportion of business students with PCs at home differs from 30%. If the test statistic is 2.5, what is the P-value for a two-tailed test?
What is 0.0124?
Compute the linear correlation coefficient for: x = 2, 3, 5, 5, 6; y = 1.3, 1.6, 2.1, 2.2, 2.7. Does a linear relation exist?
What is r = 0.983; linear relation exists?
What sample size is required to estimate the mean score on a standardized test within 4 points of the true mean with 90% confidence, if s = 15?
139