M8 Exam

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Portage Learning *

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110

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Statistics

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Jan 9, 2024

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M8: Exam - Requires Respondus LockDown Browser + Webcam Due No due date Points 50 Questions 5 Time Limit 90 Minutes Requires Respondus LockDown Browser Instructions You may only have the following items when taking an exam: computer, 1-2 pieces of blank scratch paper, a pen/pencil, and a calculator. You may ONLY use the equation sheets that are provided WITHIN the exam. The use of printed versions will be considered a violation of the Academic Integrity Policy. Attempt History Attempt Time Score LATEST Attempt 1 81 minutes 38 out of 50 Score for this quiz: 38 out of 50 Submitted Oct 21 at 10:34am This attempt took 81 minutes. Question 1 8/10 pts You may find the following files helpful throughout the exam: Statistics_Equation_Sheet = table.pdf)
Suppose we have independent random samples of size nq = 420 and n, = 510. The proportions of success in the two samples are p1= .38 and p, = 43. Find the 99% confidence interval for the difference in the two population proportions. Answer the following questions: 1. Multiple choice: Which equation would you use to solve this problem? A. F=F)— 2 [—+=—4+< y—Yty <(FH —%)+ z |— + g n, n; n n B. p_Pp, 4z \lm(l-px) 4 P2(1-P3) n, nz @ - ) - (M 1) c $i2 L 52 n, n, X S = Sa D. d-t=<jy<d+ t== 2. List the values you would insert into that equation. 3. State the final answer to the problem Your Answer: 1.B 2. P1=.38, P2=.43, n1=420, n2=510, z=2.576 .38(1—.38) N 43(1—.43) 38 .43 + 2.576\/ = =0
—.05 % 2.576(.0010)| 3. so the interval is -.047424 , -.052576 From table 6.1, we see that 99% confidence corresponds to z=2.58. Notice that the sample sizes are each greater than 30, SO wWe may use eqn. 8.2: i 2 P1(1"P1)+P2(1“P2) P. 1 n, B 38(1 = 38) .43(1 43) 510 —.05 + 2.58(.03227) So, the interval is (.-.1333,.03326). Question 2 10 / 10 pts 4 You may find the following files helpful throughout the exam: Statistics_Equation_Sheet 5 (https://iprevious.nursingabc.com/upload/images/Help_file picture/Statistic standard normal table = (https://previous.nursingabc.com/upload/images/Help_file picture/standar: t-table = (https://previous.nursingabc.com/upload/images/Help_file picture/t- table.pdf)
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4 In certain hospital, nurses are required to constantly make rounds to check in on all of the patients. The nursing supervisor would like to know there is a difference between the number of rounds completed per shift k the nurses on the day shift compared to the nurses on the night shift. So the nursing supervisor checks the records of 77 day shift nurses and finc that they complete an average (a mean) of 32 rounds per shift with a standard deviation of 4.1 rounds per shift. The nursing supervisor also checks the records of 72 night shift nurses and finds that they complete an average (a mean) of 26 rounds per shift with a standard deviation of 6.3 rounds per shift. a) Find the 95% confidence interval for estimating the difference in the population means (1 - Mo). b) Can you be 95% confident that there is a difference in the means of tt two populations? Answer the following questions: 1. Multiple choice: Which equation would you use to solve this problem? A, (x,-%) 512+322+< < (% —%,)+ 312+S22 1 2 , n, Hy Ha 1 2 , , B. P Pk Z\jm(l-m)_l_pz(l-pz) n; nz 3 -%) - (g o) C. Jfi+§z_2. ny n; Jot oo iz d s 52 2. List the values you would insert into that equation. 2 Qtata the final ancwer tn thea nrnhlam
Your Answer: 1. A 2.n1=77,n2=72,s1=4.1, s2=6.3, x1=32, x2=26, z=1.960 2 2 |(32 26) 1.960\/% + %5 < p2 < (32— 26) + 1.9604 3.14.2806 < p1 pa < 7.7194) interval is positive so we can be confident that there is a difference in the means of the 2 populations < 4
When we look back at table 6.1, we see that 95% confidence corresponds to z=1.96. If we say that the day shift nurses corresponds to population 1 and the night shift nurses corresponds to population 2, then: n{=77, no=72, s1=4.1, $,=6.3, X1=32, X,=26 a)We will use equation 8.1: S _ ’51: 5,7 L - 5,° X.—X>)—2Z|—+ < B L (Xy— X))+ Z + (%, _) . i My U2 ( 1 2) n, 4.1° o 6.3° 77 72 (32— 26)— 1.96 <py—ps<(32-26)+1 4281 <pu,—u.< 17719 1. b) Since the entire confidence interval is positive, we can be 95% sure that there is a difference in the means of the two populations. Question 3 8/10 pts You may find the following files helpful in throughout the exam: Statistics_Equation_Sheet = (https://previous.nursingabc.com/upload/images/Help_file_ picture/Statistics standard normal table /=
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t-table > table.pdf) A head librarian supervises a number of libraries in a large county. He wants to know if full-time library workers and part-time library workers re- shelve books at the same rate. So, he checks the records of 45 full-time library workers and finds that they re-shelve an average of 166 books per hour with a standard deviation of 9.3 books per hour. The records of 45 part-time library show that they re-shelve an average of 159 books per hour with a standard deviation of 12.2 books per hour. Using a level of significance of a=.01, is there enough evidence to indicate a difference in the mean number of books re-shelved by full-time workers compared to part-time workers? Answer the following questions: 1. Multiple choice: Which equation would you use to solve this problem? A (x,-%) S‘2+Szz+< < (%, —%,) + S‘2+s22 1 2 n , Hi H2 1 2 , , B. S N Jm(l—m) 4 P2(-p2) n, n; @ -x) - (M 1) C. Jfi.flfi ny n, P TR Y D \/H Ha \/H 2. List the values you would insert into that equation. 3. State the final answer to the problem
Your Answer: 1.C 2. x1=166, x2=159, s1=9.3 ,s2=12.2, n1=45 , n2=45 .01/2=.005 z=2.576, z=-2.576 166—159)—0 LRI D T —3.040 9.32 +12.22 1/5.30 45 45 3. z-score is > null hypothesis so we will reject
The null hypothesis is that there is no difference between the mean number of books re-shelved by the full-time and part- time workers: Ho:pq-u2=0 Hq : gy - g2 #0. Since this is a two-tailed test, we must find the z that satisfies: P(Z<z)=.01/2=.005 and P(Z > 2)=.01/2=.005. In the standard normal table, z=-2.576 and z=2.576. We will reject the null hypothesis if the z-score is less than -2.576 or the z-score is greater than 2.576. We now find the z-score: (f1—%)—-0 (166 —159) 0 51% . §p* J9.32 12.22 J n, o 15 * 715 = 3.06. Since the z-score is above 2.576, we reject the null hypothesis. State the null and alternative hypothesis. State the critical value. Question 4 6/10 pts You may find the following files helpful throughout the exam: Statistics_Equation_Sheet & (https://iprevious.nursingabc.com/upload/images/Help_file picture/Statistics standard normal table = (https://previous.nursingabc.com/upload/images/Help_file picture/standardn
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t-table = (https://previous.nursingabc.com/upload/images/Help_file picture/t- table.pdf) Consider the following dependent random samples Observations 1 2 3 4 5 6 x-values 155 140 142 159 162 169 y-values 169 150 151 145 173 180 a) Determine the difference between each set of points, Xx; - y; b) Do hypothesis testing to see if uyy < 0 at the a = .05. Your Answer: n=6 t=.05=2.447 fpr 6-1=5 (L tail) me 5,— /20 t<t.05 so accept null hypothesis
Since we are testing whether or not ud < 0, then our null and alternate hypothesis will be set as follows: Ho: Mlg=0 H4y:pg<0 There are 6 data points. So, n=6. This is a left-tailed test. Note that for t.o5 = -2.015 for 6-1 = 5. We find the mean in the usual way: Then using the mean, d = -6.833, and the standard deviation, sq= 10.34, that we found above: —6.833 = —1.619. d TGl (1038706 Since t > t.p5, we do not reject the null hypothesis. State the null and alternative hypothesis. State the critical value. Double check the Sd value and the d-bar value. Question 5 6/10 pts You may find the following files helpful throughout the exam: Statistics_Equation_Sheet & (https://previous.nursingabc.com/upload/images/Help_file_picture/Statistics standard normal table = (https://previous.nursingabc.com/upload/images/Help_file picture/standardn t-table = (https://previous.nursingabc.com/upload/images/Help_file_ picture/t-
A new energy drink is supposed to improve a person’s time in the one mile run. The times, in seconds, of eight runners with and without the drink are given below: Runner 1 2 3 4 5 6 7 8 x-time (before) 260 280 275 295 267 247 250 241 y-time (after) 255 270 281 275 260 243 255 239 Find the 90 % confidence interval for mean of the differences, ug. Answer the following questions: 1. Multiple choice: Which equation would you use to solve this problem? A (x,-%) S‘2+Szz+< < (%, —%,) + S‘2+s22 1 2 n , Hi H2 1 2 , , B. Pl - PZ + ZJPl(l'p1)+Pz(1’pz) ny nz @ -x) - (M 1) C. Jfi.flfi ny n; Tt i e d g ¢ 2 D \/E Ha \/H 2. List the values you would insert into that equation. 3. State the final answer to the problem Your Answer: 1.D
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2. n=8, d1=x1-y1 mean=-4.625 standard deviation=11.236 dof=8-1=7 t=2.998 _ _ 11.236 . 11.236 4.625 2.998120 < pi; < —4.625 + 2.998 1128 3.|—16.535 < pg < 7.285 Note that n=8. We will define , d; = x; - y;. After doing the appropriate calculations, we find that d =4.625 s4= 8.314. When we look at the student’s t chart for 90% confidence (the 90% is found along the bottom row of the chart) and DOF=8- 1=7 (the df=7 is found in the leftmost column) we find that t=1.895. Then D. - Sd - Sd d-t —= < <d+t— e Vn 8.314 8.314 4625- 1895 —— < < 4625+ 1.895 —— v V8 4625 - 557 < py < 4.625+ 5.57 Quiz Score: 38 out of 50