# Research On Normal Distribution Of Energy & Vitamin C Intake

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QUESTION 11.The researcher is interested to know if energy intake (ENERGY) and vitamin C intake (VITC) have a Normal distribution. Use the following Table as a guide.MeasuresCriteria/Cut-off points for supporting normalityHistogramSymmetrical, bell-shaped curveBoxplotMedian in the centre of the box with whiskers at equal length at both ends of the box and no outliersNormal Q-Q plotMost observations appear on the straight lineSkewness and kurtosis coefficientSTATA users: Skewness and (kurtosis-3) are between -1 and 1; (SPSS users: Skewness and kurtosis are between -1 and 1) 2.3.Which of the following would be appropriate?a.ENERGYandVITCboth have a Normal distribution, and hencea natural logarithm transformation is not necessary for bothENERGYandVITCb.ENERGYandVITCboth do not have a Normal distribution, and hencea natural logarithm transformation is necessary for bothENERGYandVITCc.ENERGYhas a Normal distribution andVITChas a right (positively) skewed distribution, and hencea natural logarithm transformation is necessaryonlyforVITCd.ENERGYhas a Normal distribution andVITChas a left (negatively) skewed distribution, and hencea natural logarithm transformation is necessaryonlyforENERGYe.None of the above1 points QUESTION 21.Based on previous question, you now understandwhether the variablesENERGYandVITCare normally distributed. What should be the most appropriate measures of centrality and variability to report for variableENERGYandVITC? (Hint: different measures of centrality and variability need to be reported for data that have a Normal or a skewed distribution).a.Mean and standard deviation forENERGY. The reason is that variableENERGYhas a normal (symmetric) distributionb.Median and interquartile range forVITC. The reason is that variableVITCdoes not have a normal distribution but a skewed distributionc.Median and interquartile range forENERGY. The reason is that variableENERGYhas a normal (symmetric) distributiond.Mean and standard deviation forVITC. The reason is that variableVITCdoes not have a normal distribution and it has a skewed distributione.Answer (a) and (b) are correctf.Answer (c) and (d) are correct1 points QUESTION 31.Obtain summary statistics forvariableENERGY.Which of the following isNOTCORRECT?a.The sample mean energy intake of these children is 4764.879 kJ
b.There were 50% of the children, whose energy intake is higher than 4804.95 kJ in this samplec.There was no any child in this sample whose energy intake lower than 2816.8 kJd.The sample standard deviation ofenergy intakeis 850.676kJ, then we can concludethat99% of the children in this samplewhose energy intakeranged from 3063.528(i.e., mean-2*SD) to 6466.232 (i.e., mean+2*SD)kJ1 points QUESTION 41.Obtain 95% confidence interval forvariableENERGY.Which of the following statement is correct about the estimation of the mean energy intake in the population of the2 to 3 year old children in WA?a.According to the sample information, the average daily energy intake in the population of the2 to 3 year old children in WA was estimated to be between 4555.757 and 4974.001 kJb.Based on the sample information, we are 95% confident that the sample mean daily energyintake of 2 to 3 year old children was between 4555.757 and 4974.001 kJc.Based on the sample information, the mean daily energy intake in the population of the 2 to 3 year old children in WA was estimated with 95% certainty to be between 4555.757 and 4974.001 kJd.Based on the sample information, there are 95% of the 2 to 3 year old children in WA population having a daily energy intake between 4555.757 and 4974.001 kJe.None of the above is correct1 points QUESTION 51.Which of the following statement related to confidence interval is correct?a.If the sample size of this study increased from 66 to 660, we will expect the 95% CI to becomewider as there is a larger variation now with a larger sample sizeb.If the sample size of this study increased from 66 to 660, we will expect the 95% CI to becomenarrower and be more precise than when the sample size was 66c.The higher the confidence levels (e.g. from 90% to 95% to 99%), the more confident we are about capturing the actual population parameter and therefore the correspondinglengths of the CIs tend to be shorterd.The higher the confidence levels (e.g. from 90% to 95% to 99%), the more confident we are about capturing the actual population parameter and therefore the corresponding CIs tend tobe widere.Answers(b) and (d) are both correct1 points QUESTION 61.The dietician now wants to investigate whether there is an association in energy intake between the children who live in the country and those that live in the city. You need to first recode the variableENERGYinto a categorical variableENERGYCataccording to the following table(Hint: Give the recoded variable a new name and rememberto assign value labels to the new recoded variable).Values of theoriginal variableENERGY to be recodedinto following levelsValues of thenew recodedvariableENERGYCatLess than or equal to 4500 kJ (<= 4500)1
Greater than 4500 kJ & less than or equal to 5000 kJ (>4500 & <=5000)2Greater than 5000 kJ (>5000)3Which of the following would be appropriate to describe the frequency distribution of this categorical variableENERGYCat?a.Frequency and percentage, and the percentage of kids having energy intakegreater than 4500 kJ and less than or equal to 5000 kJ (>4500 & <=5000) is 30.30% (n=20)b.Mean (=2.06) and standard deviation (=0.839)c.Median (=2) and interquartile range (=2)d.Skewness (=-0.114) and kurtosis (=1.451)e.Minimum (=1) and maximum (=3)1 points QUESTION 71.Based on the new variable you recoded inQuestion 6, obtain a cross-tabulationofENERGYCatandLOCATION.Which of the following statements is appropriate to describe the levels of energy intake between the children who live in city and country?a.More than half of the boys (53.85% of them) lived in city while slightly more of the girls (55.56% of them) lived in city toob.Of the children who lived in country, more of them tend to have daily energy intake equal or less than 4500 kJ (40.00%), compared to those who lived in city (25.00%)c.Half (50%) of the country children had daily energy intake between 4500 to 5000 kJ, and the percentage is the same for city childrend.Children who lived in city were more likely to have total daily energy intake >5000 kJ than those kids who lived in country (City 47.22% vs Country 26.67%)e.Both (b) and (d) are correct1 points QUESTION 81.Assuming all relevant assumptions are met, how would you test whether there is any association between the levels of energy intake of childrenENERGYCatand the location they livedLOCATION?a.Pearson Correlation Coefficient can be used asENERGYandLOCATIONboth are continuousb.Chi-square test can be used asENERGYCat andLOCATIONboth are categoricalc.An independent (two samples) samples t-test can be used asENERGYis continuous,andLOCATIONis categorical having two levelsd.One-way ANOVA is suitable for this research question asLOCATIONis continuousand ENERGYCatis categorical with 3 levelse.Paired samples t-test is fine to answer this research question, asLOCATION and ENERGYCatare repeated variables1 points QUESTION 9

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