Statistics in Food Science

Attempt the following questions to check your understanding of the subject:

PART 1
  1. A food scientist got the following output after running their data in SAS.
    1. Which SAS procedure was used to generate the following output?                                                                                                 (2 Marks)
    2. Which other SAS procedures can be used to generate these same outputs?                                                                                                 (2 Marks)
    3. Briefly explain the results in the Moments table (6 Marks)

Ash Content

Moments

Moments
N36Sum Weights36
Mean3.10977778Sum Observations111.952
Std Deviation0.64475285Variance0.41570623
Skewness0.38531895Kurtosis-0.786359
Uncorrected SS362.69556Corrected SS14.5497182
Coeff Variation20.7330843Std Error Mean0.10745881

Basic Measures of Location and Variability

Basic Statistical Measures
LocationVariability
Mean3.109778Std Deviation0.64475
Median2.979500Variance0.41571
Mode.Range2.44200
  Interquartile Range1.01400

Tests For Location

Tests for Location: Mu0=0
TestStatisticp Value
Student’s tt28.93925Pr > |t|<.0001
SignM18Pr >= |M|<.0001
Signed RankS333Pr >= |S|<.0001
  1. In a study to determine the best training methods for student’s sensory panels, three panels of 30 students each were subjected to three different training methods and their ability to identify samples examined using 4 samples of juices with varied concentration of sugar (0%, 1%, 2% and 3%). The samples were presented in a random order to each panelist and the students awarded a score depending on the number of samples that they correctly identified.
    1. Identify the following             (3 Marks)
      1. Experimental units
      2. Independent variables
      3. Response variables
    2. What is the most ideal statistical design for this study? Explain (2 Marks)
    3. What is the statistical model for this experiment?             (3 Marks)
    4. Draw the experimental layout for this study             (2 Marks)
    5. Show the statistical model for this experiment (3 Marks)
    6. Show the SAS Program that you would write to carry ANOVA for this data                                                                                                 (3 Marks)
PART 2
  1. A researcher found the following results
SourceDFSum of SquaresMean SquareF ValuePr > F
Model12841.229967070.102497226.67<.0001
Error2668.35400402.6290002  
Corrected Total38909.5839710   
SourceDFType I SSMean SquareF ValuePr > F
Extender6642.8673361107.144556040.75<.0001
extension_Level191.358550091.358550034.75<.0001
Extender*extension_L5107.004080821.40081628.14<.0001
  1. Interpret the results (3 Marks)
  2. Give the statistical model that was used in this study (3 Marks)
  3. Which SAS program was used to obtain these results? (4 Marks)
  4. Given the mean cooking loss was 14.22597, calculate the following (6 Marks)
    1. R2
    2. Coefficient of variation
    3. Standard deviation
  1. A RCBD experiment was conducted in which a chemical was used to increase the shelf life of ripe pawpaw fruit. Three treatments were used: C (no chemical added), L (low dose), H (high dose). The experimental unit is a shelve containing six fruits. Because of variation in ventilation within the green grocery store, the position of each shelf was thought to influence the outcome. Shelves were therefore blocked based on their position and the three treatments were randomly assigned to each block. The following data was obtained.
BlockControl (C)Low dose (L)High dose (H)Block total
13.933.994.0812.00
23.783.963.9411.68
33.883.964.0211.86
43.934.034.0612.02
53.844.103.9411.88
63.754.024.0911.86
73.984.064.1712.211
83.843.924.1211.88
Treatment total30.9332.0432.42Grand total: 95.39
  1. Write down an appropriate statistical model and ensure that every symbol and notation used is given meaning (3 Marks)
  2. Construct the ANOVA table to test whether there is sufficient evidence of a difference between the three treatments (use Fα=0.05; 2,14 = 3.739) (5 Marks)
  3. If instead of a RCBD, aa CRD was used, calculate the relative efficiency and state whether it was necessary to use RCBD (2 Marks)