The article "A Probabilistic Analysis of Dissolved Oxygen-Biochemical Oxygen Demand Relationship in Streams" (J. Water Resources Control Fed., 1969: 73-90) reports data on the rate of oxygenation in streams at 20°C in a certain region. The sample mean and standard deviation were computed as  = .173 and s 5 .066, respectively. Based on the accompanying frequency distribution, can it be concluded that oxygenation rate is a normally distributed variable? Use the chi-squared test with a 5 .05.
Rate (per day) ...........................Frequency
Below .100....................................... 12
.100-below .150................................. 20
.150-below .200................................. 23
.200-below .250 .................................15
.250 or more .......................................13