A classroom temperature was recorded once each hour during the school day.
<table><thead><tr><th>Time \(t\)</th><th>\(8{:}00\) a.m.</th><th>\(9{:}00\) a.m.</th><th>\(10{:}00\) a.m.</th><th>\(11{:}00\) a.m.</th><th>\(12{:}00\) p.m.</th><th>\(1{:}00\) p.m.</th></tr></thead><tbody><tr><td>Temperature \(T(t)\) in \(^\circ\text{F}\)</td><td>\(65.0\)</td><td>\(66.5\)</td><td>\(68.0\)</td><td>\(92.0\)</td><td>\(71.0\)</td><td>\(72.5\)</td></tr></tbody></table>
a) One value does not fit the linear pattern in the other data. Identify the value and justify your choice mathematically.
b) After excluding the unusual value, state the range of the remaining time-temperature relation.
c) State the domain of the original relation, using hour numbers.
d) Estimate the temperature at \(11{:}00\) a.m. if the pattern in the other measurements had continued.
Hints
- Compare the hourly changes in temperature.
- The range lists output values from the retained data.
- The domain lists the hours when measurements were taken.
- Extend the consistent hourly pattern to estimate the unusual reading.
Solution
1. Except for the \(11{:}00\) a.m. value, the temperature increases by \(1.5\,^\circ\text{F}\) each hour. Therefore, \(92.0\,^\circ\text{F}\) is unusual. The data alone do not prove it was a measurement error.
2. Excluding that value, the range is \(\{65.0,66.5,68.0,71.0,72.5\}\).
3. The original domain is \(D=\{8,9,10,11,12,13\}\).
4. Extending the regular change gives \(68.0+1.5=69.5\), so the estimated temperature is \(69.5\,^\circ\text{F}\).
Answer
a) \(92.0\,^\circ\text{F}\) at \(11{:}00\) a.m.; the other values increase by \(1.5\,^\circ\text{F}\) per hour.
b) \(\{65.0,66.5,68.0,71.0,72.5\}\).
c) \(D=\{8,9,10,11,12,13\}\).
d) \(69.5\,^\circ\text{F}\).