• Having trouble with this statistic problem.?

Best answer: You should get the first two correct: xbar, s. The population is normal, unknown variance, n=10, small. Use t-test. H0:μ=63 HA:μ>63 One-tailed right. Test statistic t=(xbar-μ)/(s/√n) Compare with t(9,0.05)=1.833, the CR is {T>1.833} If t value > 1.833, reject H0, (else do not reject) The claim that the mean weight is... show more
Best answer: You should get the first two correct: xbar, s. The population is normal, unknown variance, n=10, small. Use t-test. H0:μ=63 HA:μ>63 One-tailed right. Test statistic t=(xbar-μ)/(s/√n) Compare with t(9,0.05)=1.833, the CR is {T>1.833} If t value > 1.833, reject H0, (else do not reject) The claim that the mean weight is higher with the enriched feed is supported. (not supported)
1 answer · Mathematics · 6 years ago
• Finding the Z-value in table?

CR is of the form {Z>z} You want P{Z>z}=0.01 Use inverse standard normal distribution table. z=2.326
CR is of the form {Z>z} You want P{Z>z}=0.01 Use inverse standard normal distribution table. z=2.326
2 answers · Mathematics · 6 years ago
• Standard deviation of the sample means will?

Always except for n=1. var(Xbar) = var(X)/n < var(X), n>1. Take sqrt, a monotone fn.
Always except for n=1. var(Xbar) = var(X)/n < var(X), n>1. Take sqrt, a monotone fn.
2 answers · Mathematics · 6 years ago
• Statistics: confidence interval estimation problem?

Best answer: Since n=720 is large enough, use the normal approximation to the binomial. The 90% confidence interval for the true proportion P based on a sample estimate p=97/720 = 0.1347 is given by p ± z(α/2)*√[p(1-p)/n], where z(α/2) = z(0.05) = 1.645, n = 720. Upper limit =0.1347+0.0209=0.1556, or 15.56%
Best answer: Since n=720 is large enough, use the normal approximation to the binomial. The 90% confidence interval for the true proportion P based on a sample estimate p=97/720 = 0.1347 is given by p ± z(α/2)*√[p(1-p)/n], where z(α/2) = z(0.05) = 1.645, n = 720. Upper limit =0.1347+0.0209=0.1556, or 15.56%
1 answer · Mathematics · 6 years ago
• Help with confidence intervals?

Best answer: c) Sample size n=6 small, unknown pop variance; assume normal population. Use t-distribution, ν=5 xbar ± t(α/2, ν)*(s/√n) xbar=5, s/√n = 1, t(α/2, ν)=2.571 t(α/2, ν) is the value of t when the area on its right of t-curve, df ν, is α/2 and for CI of (1-α)100%.
Best answer: c) Sample size n=6 small, unknown pop variance; assume normal population. Use t-distribution, ν=5 xbar ± t(α/2, ν)*(s/√n) xbar=5, s/√n = 1, t(α/2, ν)=2.571 t(α/2, ν) is the value of t when the area on its right of t-curve, df ν, is α/2 and for CI of (1-α)100%.
1 answer · Mathematics · 6 years ago
• Z Score Question Could Canyone Help?

X~N(170, 30^2) P{170<X<225}=P{0<Z<z}, z=(225-170)/30 = 1.667 P=0.9525-0.50=0.4525, about 45% of them.
X~N(170, 30^2) P{170<X<225}=P{0<Z<z}, z=(225-170)/30 = 1.667 P=0.9525-0.50=0.4525, about 45% of them.
2 answers · Mathematics · 6 years ago
• AP Statistics Question - Alpha Levels and Null Hypotheses?

Best answer: Slight confusion here. your z-score is above the alpha level? 1. suppose to have said - your z-score is above the critical z (assume one-tailed right) 2. your p-value is smaller than the alpha level 1 refers to the classical way to get the result of test 2 refers to the modern way to get the result of test If any of 1 or 2 happens... show more
Best answer: Slight confusion here. your z-score is above the alpha level? 1. suppose to have said - your z-score is above the critical z (assume one-tailed right) 2. your p-value is smaller than the alpha level 1 refers to the classical way to get the result of test 2 refers to the modern way to get the result of test If any of 1 or 2 happens then reject H0, else, then do not reject H0.
3 answers · Mathematics · 6 years ago
• If a null hypothesis is rejected with a significance level of 0.05 is it also rejected with a significance lev?

Not necessary Rejected with a significance level of 0.05 means p-value < 0.05, it is also possible that p-value < 0.01. Example, if p-value = 0.003, < 0.05 and < 0.01, reject both at 0.05 and 0.01. But if p-value = 0.04, < 0.05 but > 0.01, reject at 0.05 only, but not at 0.01. Happy?
Not necessary Rejected with a significance level of 0.05 means p-value < 0.05, it is also possible that p-value < 0.01. Example, if p-value = 0.003, < 0.05 and < 0.01, reject both at 0.05 and 0.01. But if p-value = 0.04, < 0.05 but > 0.01, reject at 0.05 only, but not at 0.01. Happy?
4 answers · Mathematics · 6 years ago
• Hypothesis Tesing; two sample proportions?

Two sample proportions? why You are looking at just one population From H1, the critical region is of the form {Z<z} Decision rule - reject H0 if p-value < the significance level (0.05) p-value = P{Z<-4.07}=0.00 < 0.05 Reject H0 at 5%; the claim that less than 20% of the people sampled take sleep-aids daily is supported. show more
Two sample proportions? why You are looking at just one population From H1, the critical region is of the form {Z<z} Decision rule - reject H0 if p-value < the significance level (0.05) p-value = P{Z<-4.07}=0.00 < 0.05 Reject H0 at 5%; the claim that less than 20% of the people sampled take sleep-aids daily is supported.
3 answers · Mathematics · 6 years ago
• Statistics independent samples?

Best answer: F=(11.5)^2/(3.2)^2 = 12.92, of F(15,9) α= 0.05, two-tailed Left 0.025 - 0.320, right 0.025 - 3.77 12.92 is inside the CR of the test; reject H0 at 5%. the two population standard deviations differs
Best answer: F=(11.5)^2/(3.2)^2 = 12.92, of F(15,9) α= 0.05, two-tailed Left 0.025 - 0.320, right 0.025 - 3.77 12.92 is inside the CR of the test; reject H0 at 5%. the two population standard deviations differs
1 answer · Mathematics · 6 years ago
• How to find the critical z value?

For right-tail z-test the critical region is of the form {Z>z}, and when P{Z>zc}=0.10, zc is the critical value for testing at significance level α = 0.10 . Draw the z-curve and mark the critical value. On the horizontal axis (z), all points to the right of zc is the critical region. Shade the area bounded by the vertical line at zc, the... show more
For right-tail z-test the critical region is of the form {Z>z}, and when P{Z>zc}=0.10, zc is the critical value for testing at significance level α = 0.10 . Draw the z-curve and mark the critical value. On the horizontal axis (z), all points to the right of zc is the critical region. Shade the area bounded by the vertical line at zc, the curve and the critical region. The shaded area is = 0.10. Standard normal table comes in 3 forms (may be). For corresponding z, F(z) - z from about -4.000 to about +4.000, or [P{Z<z}] F(z) - z from 0 to about +4.000, or [P{Z<z}] 1-F(z) or P{Z>z} If you have the 3rd form, easy to get zc, direct; From 1st form, just look at F(0.90), P{Z<zc}=0.90, from symmetry, P{Z<-zc}=0.10. From 2nd from, make adjustment for 0.5, when necessary. In you have the inverse table, much simpler. In all cases, zc=1.282.
5 answers · Mathematics · 6 years ago
• Statistics Variability?

Can we do like this? If sample size is n, total = 8n New total = (8n+6n)/2 New mean = new total / n = 7
Can we do like this? If sample size is n, total = 8n New total = (8n+6n)/2 New mean = new total / n = 7
1 answer · Mathematics · 6 years ago
• Statistics: Normal distribution?

X~N(98.23, 0.61^2) Proportion having fever P{X>100.6}=P{Z>z} where z=(100.6-98.23)/0.61=3.89 P=P{Z>3.89}=P{Z<-3.89}=0.000, almost none. For 5% having fever P{X>x}=P{Z>z}=0.05, z=1.645 (x-98.23)/0.61 = 1.645, x=99.23 F.
X~N(98.23, 0.61^2) Proportion having fever P{X>100.6}=P{Z>z} where z=(100.6-98.23)/0.61=3.89 P=P{Z>3.89}=P{Z<-3.89}=0.000, almost none. For 5% having fever P{X>x}=P{Z>z}=0.05, z=1.645 (x-98.23)/0.61 = 1.645, x=99.23 F.
1 answer · Mathematics · 6 years ago

Best answer: 3. Poisson problem 0.33 per second = 19.8 per minute (7:15 and 7:16) Poisson λ=19.8 (take 20) P{X=30}=...
Best answer: 3. Poisson problem 0.33 per second = 19.8 per minute (7:15 and 7:16) Poisson λ=19.8 (take 20) P{X=30}=...
1 answer · Mathematics · 6 years ago
• System of linear equations elimination method with fractions?

Best answer: (1)X6, 3x+2y=78 (2)X40, 8x+5y=200 do as usual.
Best answer: (1)X6, 3x+2y=78 (2)X40, 8x+5y=200 do as usual.
3 answers · Mathematics · 6 years ago
• What indicates the variability of a mean?

Best answer: var(Xbar) or its sqrt, estimated by 0.302/10
Best answer: var(Xbar) or its sqrt, estimated by 0.302/10
1 answer · Mathematics · 6 years ago
• Class is Probability and Statistic for engineers, Hypothesis Test?

Best answer: It would be enjoyable to help you through if you first calculate xbar and s, it's a good exercise. A. H0: μ=50, HA: μ≠50 Assume normal population. Unknown variance, n=12 small. Use t-test. t=(xbar-μ)/(s/√n) = ? Two-tailed test, CR of the form {|T|>t} t(11, 0.025) = 2.201 CR is {|T|>2.201}, cf with calculated t. If you... show more
Best answer: It would be enjoyable to help you through if you first calculate xbar and s, it's a good exercise. A. H0: μ=50, HA: μ≠50 Assume normal population. Unknown variance, n=12 small. Use t-test. t=(xbar-μ)/(s/√n) = ? Two-tailed test, CR of the form {|T|>t} t(11, 0.025) = 2.201 CR is {|T|>2.201}, cf with calculated t. If you get like t=2.50, inside the CR, reject H0 If like t=1.78, outside the CR, do not reject H0. CI, xbar ± t(α/2, ν)*(s/√n) t(α/2, ν) is the value of t when the area on its right of t-curve, df ν, is α/2 and for CI of (1-α)100%. For t=2.50, the stat val,ν=11, p-value = P{|T|>2.50} = 2* P{T>2.50} = (between 0.05 and 0.02), meaning < 0.05. (actual value is not necessary, information <, > alpha, would do.)
1 answer · Engineering · 6 years ago
• A police department reports that the probabilites that 0,1,2, and 3 burglaries will be reported in a given...?

0,1,2, and 3 0.49,0.38,0.10, and 0.03 (sum =1) E(X)=0(0.49)+1(0.38) + ... E(X^2)=0^2(0.49)+1^2(0.38) + ... var(X)=E(X^2) - E(X)*E(X) take sqrt
0,1,2, and 3 0.49,0.38,0.10, and 0.03 (sum =1) E(X)=0(0.49)+1(0.38) + ... E(X^2)=0^2(0.49)+1^2(0.38) + ... var(X)=E(X^2) - E(X)*E(X) take sqrt
1 answer · Mathematics · 6 years ago
• Don't understand t-test, help?

If you are given significance level, α Determine the form of critical region: {|T|>t} for two-tailed {T>t} for one-tailed right {T<t} for one-tailed left Get the p-value accordingly: P{|T|>t}, P{T>t}, or P{T<t} Compare p-value with α, if p-value < α, reject H0 at α, else do not reject H0 at α. (Reject H0 at α means... show more
If you are given significance level, α Determine the form of critical region: {|T|>t} for two-tailed {T>t} for one-tailed right {T<t} for one-tailed left Get the p-value accordingly: P{|T|>t}, P{T>t}, or P{T<t} Compare p-value with α, if p-value < α, reject H0 at α, else do not reject H0 at α. (Reject H0 at α means significant at α)
3 answers · Mathematics · 6 years ago
• Statistics: Test Statistic and P Value?

Best answer: For n=19, 29 need to assume normal population. z=(4.5-0)/(23/√n) Based on H1 critical region is of the form {Z>z} p-value=P{Z>z} n=19, z=0.85, p-value=P{Z>0.85}=P{Z<-0.85}=0.20. (note symmetry) n=49, z=1.37, ... =0.085
Best answer: For n=19, 29 need to assume normal population. z=(4.5-0)/(23/√n) Based on H1 critical region is of the form {Z>z} p-value=P{Z>z} n=19, z=0.85, p-value=P{Z>0.85}=P{Z<-0.85}=0.20. (note symmetry) n=49, z=1.37, ... =0.085
2 answers · Mathematics · 6 years ago