phy lab std calc thing

(function() {
    const vals = [10.06, 9.788, 9.98, 9.958, 10.128];

    const mean = vals.reduce((a, b) => a + b) / vals.length;

    let variance = 0;
    for(let val of vals) {
        variance += (val - mean) ** 2;
    }
    variance /= vals.length;

    const std = Math.sqrt(variance);

    // Mean and standard deviation
    console.log("Mean: " + mean.toFixed(3));
    console.log("σ: " + std.toFixed(3));

    // Lower and upper bound
    console.log("Lower bound: " + (mean - std * 2).toFixed(3));
    console.log("Upper bound: " + (mean + std * 2).toFixed(3));
})();